[RFA] set/unset/show substitute-path commands (take 2)

[RFA] set/unset/show substitute-path commands (take 2)

[Joel Brobecker]

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Hello,

:ADDPATCH source.c:

Here is a second crack at implementing the substitute-path feature
taking into account all suggestions made so far (hopefully). It also
includes Eli's suggestion to have "show substitute-path FROM".

I have added a first attempt at making a test. It only tests the
manipulation of the list of substitution rules, but not the applying
of them while debugging a program, because I am not sure how to do
that without resorting to shell commands such as mkdir et al. It's
still better than nothing, though.

Documentatio will be revised as soon as the code goes it. It's a waste
of time to have Eli review it if anything during the review changes
the feature in such a way that the documentation needs to be updated.

2006-07-14  Joel Brobecker  <brobecker@adacore.com>

        * source.c: #include gdb_assert.h.
        (substitute_path_rule): New struct.
        (substitute_path_rules): New static global variable.
        (substitute_path_rule_matches): New function.
        (get_substitute_path_rule): New function.
        (rewrite_source_path): New function.
        (find_and_open_source): Add source path rewriting support.
        (strip_trailing_directory_separator): New function.
        (make_cleanup_argv): New function.
        (add_substitute_path_rule): New function.
        (delete_substitute_path_rule): New function.
        (show_substitute_path_command): New function.
        (unset_substitute_path_command): New function.
        (set_substitute_path_command): New function.
        (_initialize_source): Add new substitute-path commands.

2006-07-14  Joel Brobecker  <brobecker@adacore.com>

        * gdb.base/subst.exp: New testcase.

OK to commit?

Thanks,
-- 
Joel

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Index: source.c
===================================================================
RCS file: /cvs/src/src/gdb/source.c,v
retrieving revision 1.75
diff -u -p -r1.75 source.c
--- source.c	15 May 2006 15:50:13 -0000	1.75
+++ source.c	15 Jul 2006 05:35:50 -0000
@@ -29,6 +29,7 @@
 #include "gdbcmd.h"
 #include "frame.h"
 #include "value.h"
+#include "gdb_assert.h"
 
 #include <sys/types.h>
 #include "gdb_string.h"
@@ -73,6 +74,17 @@ static void show_directories (char *, in
 
 char *source_path;
 
+/* Support for source path substitution commands.  */
+
+struct substitute_path_rule
+{
+  char *from;
+  char *to;
+  struct substitute_path_rule *next;
+};
+
+static struct substitute_path_rule *substitute_path_rules = NULL;
+
 /* Symtab of default file for listing lines of.  */
 
 static struct symtab *current_source_symtab;
@@ -828,6 +840,74 @@ source_full_path_of (char *filename, cha
   return 1;
 }
 
+/* Return non-zero if RULE matches PATH, that is if the rule can be
+   applied to PATH.  */
+
+static int
+substitute_path_rule_matches (const struct substitute_path_rule *rule,
+                              const char *path)
+{
+  const int from_len = strlen (rule->from);
+
+  /* The substitution rules are anchored at the start of the path,
+     so the path should start with rule->from.  */
+
+  if (strncmp (path, rule->from, from_len) != 0)
+    return 0;
+
+  /* Make sure that the region in the path that matches the substitution
+     rule is immediately followed by a directory separator (or the end of
+     string character).  */
+  
+  if (path[from_len] != '\0' && !IS_DIR_SEPARATOR (path[from_len]))
+    return 0;
+
+  return 1;
+}
+
+/* Find the substitute-path rule that applies to PATH and return it.
+   Return NULL if no rule applies.  */
+
+static struct substitute_path_rule *
+get_substitute_path_rule (const char *path)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+
+  while (rule != NULL && !substitute_path_rule_matches (rule, path))
+    rule = rule->next;
+
+  return rule;
+}
+
+/* If the user specified a source path substitution rule that applies
+   to PATH, then apply it and return the new path.  This new path must
+   be deallocated afterwards.  
+   
+   Return NULL if no substitution rule was specified by the user,
+   or if no rule applied to the given PATH.  */
+   
+static char *
+rewrite_source_path (const char *path)
+{
+  const struct substitute_path_rule *rule = get_substitute_path_rule (path);
+  char *new_path;
+  int from_len;
+  
+  if (rule == NULL)
+    return NULL;
+
+  from_len = strlen (rule->from);
+
+  /* Compute the rewritten path and return it.  */
+
+  new_path =
+    (char *) xmalloc (strlen (path) + 1 + strlen (rule->to) - from_len);
+  strcpy (new_path, rule->to);
+  strcat (new_path, path + from_len);
+
+  return new_path;
+}
+
 /* This function is capable of finding the absolute path to a
    source file, and opening it, provided you give it an 
    OBJFILE and FILENAME. Both the DIRNAME and FULLNAME are only
@@ -844,7 +924,7 @@ source_full_path_of (char *filename, cha
      FULLNAME is set to the absolute path to the file just opened.
 
    On Failure
-     A non valid file descriptor is returned. ( the return value is negitive ) 
+     An invalid file descriptor is returned. ( the return value is negative ) 
      FULLNAME is set to NULL.  */
 int
 find_and_open_source (struct objfile *objfile,
@@ -857,8 +937,22 @@ find_and_open_source (struct objfile *ob
   int result;
 
   /* Quick way out if we already know its full name */
+
   if (*fullname)
     {
+      {
+        /* The user may have requested that source paths be rewritten
+           according to substitution rules he provided.  If a substitution
+           rule applies to this path, then apply it.  */
+        char *rewritten_fullname = rewrite_source_path (*fullname);
+
+        if (rewritten_fullname != NULL)
+           {
+             xfree (*fullname);
+             *fullname = rewritten_fullname;
+           }
+      }
+
       result = open (*fullname, OPEN_MODE);
       if (result >= 0)
 	return result;
@@ -869,6 +963,17 @@ find_and_open_source (struct objfile *ob
 
   if (dirname != NULL)
     {
+      /* If necessary, rewrite the compilation directory name according
+         to the source path substitution rules specified by the user.  */
+
+      char *rewritten_dirname = rewrite_source_path (dirname);
+
+      if (rewritten_dirname != NULL)
+        {
+          make_cleanup (xfree, rewritten_dirname);
+          dirname = rewritten_dirname;
+        }
+      
       /* Replace a path entry of  $cdir  with the compilation directory name */
 #define	cdir_len	5
       /* We cast strstr's result in case an ANSIhole has made it const,
@@ -1587,6 +1692,207 @@ reverse_search_command (char *regex, int
   fclose (stream);
   return;
 }
+
+/* If the last character of PATH is a directory separator, then strip it.  */
+
+static void
+strip_trailing_directory_separator (char *path)
+{
+  const int last = strlen (path) - 1;
+
+  if (last < 0)
+    return;  /* No stripping is needed if PATH is the empty string.  */
+
+  if (IS_DIR_SEPARATOR (path[last]))
+    path[last] = '\0';
+}
+
+/* A convenience function to push ARGV in the cleanup queue.  */
+
+static void
+make_cleanup_argv (char **argv)
+{
+  make_cleanup ((make_cleanup_ftype *) freeargv, argv);
+}
+
+/* Add a new substitute-path rule at the end of the current list of rules.
+   The new rule will replace FROM into TO.  */
+
+static void
+add_substitute_path_rule (char *from, char *to)
+{
+  struct substitute_path_rule *last;
+  struct substitute_path_rule *rule;
+
+  rule = xmalloc (sizeof (struct substitute_path_rule));
+  rule->from = xstrdup (from);
+  rule->to = xstrdup (to);
+  rule->next = NULL;
+
+  /* If the list of rules are empty, then insert the new rule
+     at the head of the list.  */
+
+  if (substitute_path_rules == NULL)
+    {
+      substitute_path_rules = rule;
+      return;
+    }
+
+  /* Otherwise, skip to the last rule in our list and then append
+     the new rule.  */
+
+  last = substitute_path_rules;
+  while (last->next != NULL)
+    last = last->next;
+
+  last->next = rule;
+}
+
+/* Remove the given source path substitution rule from the current list
+   of rules.  The memory allocated for that rule is also deallocated.  */
+
+static void
+delete_substitute_path_rule (struct substitute_path_rule *rule)
+{
+  if (rule == substitute_path_rules)
+    substitute_path_rules = rule->next;
+  else
+    {
+      struct substitute_path_rule *prev = substitute_path_rules;
+
+      while (prev != NULL && prev->next != rule)
+        prev = prev->next;
+
+      gdb_assert (prev != NULL);
+
+      prev->next = rule->next;
+    }
+
+  xfree (rule->from);
+  xfree (rule->to);
+  xfree (rule);
+}
+
+/* Implement the "show substitute-path" command.  */
+
+static void
+show_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv;
+  char *from = NULL;
+  
+  argv = buildargv (args);
+  make_cleanup_argv (argv);
+
+  /* We expect zero or one argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* Print the substitution rules.  */
+
+  if (from != NULL)
+    printf_filtered
+      (_("Source path substitution rules matching `%s':\n"), from);
+  else
+    printf_filtered (_("List of all source path substitution rules:\n"));
+
+  while (rule != NULL)
+    {
+      if (from == NULL || strcmp (rule->from, from) == 0)
+        printf_filtered ("  `%s' -> `%s'.\n", rule->from, rule->to);
+      rule = rule->next;
+    }
+}
+
+/* Implement the "unset substitute-path" command.  */
+
+static void
+unset_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv = buildargv (args);
+  char *from = NULL;
+  int rule_found = 0;
+
+  /* This function takes either 0 or 1 argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* If the user asked for all the rules to be deleted, ask him
+     to confirm and give him a chance to abort before the action
+     is performed.  */
+
+  if (from == NULL
+      && !query (_("Delete all source path substitution rules? ")))
+    error (_("Canceled"));
+
+  /* Delete all the rules matching the argument.
+     No argument means that all rules should be deleted.  */
+
+  while (rule != NULL)
+    {
+      struct substitute_path_rule *next = rule->next;
+
+      if (from == NULL || strcmp (from, rule->from) == 0)
+        {
+          delete_substitute_path_rule (rule);
+          rule_found = 1;
+        }
+
+      rule = next;
+    }
+  
+  /* If no rule matching the argument was found, then print an error
+     message to the user.  */
+
+  if (!rule_found)
+    {
+      if (from != NULL)
+        error (_("No substitution rule defined for `%s'"), from);
+      else
+        error (_("No substitution rule defined"));
+    }
+}
+
+/* Add a new source path substitution rule.  */
+
+static void
+set_substitute_path_command (char *args, int from_tty)
+{
+  char *from_path, *to_path;
+  char **argv;
+  
+  argv = buildargv (args);
+  make_cleanup_argv (argv);
+
+  if (argv == NULL || argv[0] == NULL || argv [1] == NULL)
+    error (_("Incorrect usage, too few arguments in command"));
+
+  if (argv[2] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (*(argv[0]) == '\0')
+    error (_("First argument must be at least one character long"));
+
+  /* Strip any trailing directory separator character in either FROM
+     or TO.  The substitution rule already implicitly contains them.  */
+  strip_trailing_directory_separator (argv[0]);
+  strip_trailing_directory_separator (argv[1]);
+
+  /* Insert the new substitution rule.  */
+
+  add_substitute_path_rule (argv[0], argv[1]);
+}
+
 \f
 void
 _initialize_source (void)
@@ -1666,4 +1972,19 @@ Show number of source lines gdb will lis
 			    NULL,
 			    show_lines_to_list,
 			    &setlist, &showlist);
+
+  add_cmd ("substitute-path", class_files, set_substitute_path_command,
+           _("\
+Add a source path substitution rule.  If a substitution rule was previously\n\
+set, it is overridden."), &setlist);
+
+  add_cmd ("substitute-path", class_files, unset_substitute_path_command,
+           _("\
+Remove the current source path substitution rule.  This has no effect\n\
+if no path substitution rule was previously specified."),
+           &unsetlist);
+
+  add_cmd ("substitute-path", class_files, show_substitute_path_command,
+           _("Show the current source path substitution rule."),
+           &showlist);
 }
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.822
diff -u -p -r1.822 Makefile.in
--- Makefile.in	23 Jun 2006 13:01:05 -0000	1.822
+++ Makefile.in	15 Jul 2006 05:35:51 -0000
@@ -2630,7 +2630,8 @@ source.o: source.c $(defs_h) $(symtab_h)
 	$(command_h) $(source_h) $(gdbcmd_h) $(frame_h) $(value_h) \
 	$(gdb_string_h) $(gdb_stat_h) $(gdbcore_h) $(gdb_regex_h) \
 	$(symfile_h) $(objfiles_h) $(annotate_h) $(gdbtypes_h) $(linespec_h) \
-	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h)
+	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h) \
+	$(gdb_assert_h)
 sparc64fbsd-nat.o: sparc64fbsd-nat.c $(defs_h) $(regcache_h) $(target_h) \
 	$(fbsd_nat_h) $(sparc64_tdep_h) $(sparc_nat_h) $(bsd_kvm_h)
 sparc64fbsd-tdep.o: sparc64fbsd-tdep.c $(defs_h) $(frame_h) \

[-- Attachment #3: subst.exp --]
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# Copyright 2006 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301, USA

if $tracelevel {
    strace $tracelevel
}

gdb_exit
gdb_start
gdb_reinitialize_dir $srcdir/$subdir

# Do a bunch of testing of the set/unset/show substitute-path
# commands that do not require the presence of an executable.

gdb_test "set confirm off" \
         "" \
         "deactivate GDB's confirmation interface"

gdb_test "show substitute-path" \
         "List of all source path substitution rules:" \
         "show substitute-path, no rule entered yet"

gdb_test "show substitute-path from" \
         "Source path substitution rules matching `from':" \
         "show substitute-path from, no rule entered yet"

gdb_test "show substitute-path too many" \
         "Too many arguments in command" \
         "show substitute-path, too many arguments"

gdb_test "unset substitute-path from" \
         "No substitution rule defined for `from'" \
         "unset substitute-path from, no rule entered yet"

gdb_test "unset substitute-path" \
         "No substitution rule defined" \
         "unset substitute-path, no rule entered yet"

gdb_test "unset substitute-path from" \
         "No substitution rule defined for `from'" \
         "unset substitute-path from, no rule entered yet"

gdb_test "unset substitute-path from to" \
         "Incorrect usage, too many arguments in command" \
         "unset substitute-path, too many arguments"

gdb_test "set substitute-path too many arguments" \
         "Incorrect usage, too many arguments in command" \
         "set substitute-path, too many arguments"

gdb_test "set substitute-path missing" \
         "Incorrect usage, too few arguments in command" \
         "set substitute-path, too few arguments"

gdb_test "set substitute-path '' to" \
         "First argument must be at least one character long" \
         "set substitute-path, first argument is empty string"

gdb_test "set substitute-path from to" \
         "" \
         "add from -> to substitution rule"

gdb_test "set substitute-path from1 to1/" \
         "" \
         "add from1 -> to1 substitution rule"

gdb_test "set substitute-path source destination" \
         "" \
         "add source -> destination substitution rule"

gdb_test "set substitute-path depuis/ vers" \
         "" \
         "add depuis -> vers substitution rule"

gdb_test "set substitute-path empty ''" \
         "" \
         "add substitution rule to empty string"

gdb_test "show substitute-path" \
         "List of all source path substitution rules:\r\n +`from' -> `to'.\r\n +`from1' -> `to1'.\r\n +`source' -> `destination'.\r\n\ +`depuis' -> `vers'.\r\n +`empty' -> `'." \
         "show substitute-path after all paths added"

gdb_test "show substitute-path from" \
         "Source path substitution rules matching `from':\r\n +`from' -> `to'." \
         "show substitute-path from, after all paths added"

gdb_test "show substitute-path depuis" \
         "Source path substitution rules matching `depuis':\r\n +`depuis' -> `vers'." \
         "show substitute-path depuis, after all paths added"

gdb_test "show substitute-path garbage" \
         "Source path substitution rules matching `garbage':" \
         "show substitute-path garbage, after all paths added"

gdb_test "unset substitute-path from" \
         "" \
         "unset substitute-path from"

gdb_test "show substitute-path from" \
         "Source path substitution rules matching `from':" \
         ""

gdb_test "show substitute-path" \
         "List of all source path substitution rules:\r\n +`from1' -> `to1'.\r\n +`source' -> `destination'.\r\n\ +`depuis' -> `vers'.\r\n +`empty' -> `'." \
         "show substitute-path after from rule removed"

gdb_test "unset substitute-path from" \
         "No substitution rule defined for `from'" \
         "unset substitute-path from after the rule was removed"

gdb_test "unset substitute-path depuis" \
         "" \
         "unset substitute-path depuis (middle of list)"

gdb_test "show substitute-path" \
         "List of all source path substitution rules:\r\n +`from1' -> `to1'.\r\n +`source' -> `destination'.\r\n\ +`empty' -> `'." \
         "show substitute-path after depuis rule removed"

gdb_test "unset substitute-path empty" \
         "" \
         "unset substitute-path empty (end of list)"

gdb_test "show substitute-path" \
         "List of all source path substitution rules:\r\n +`from1' -> `to1'.\r\n +`source' -> `destination'." \
         "show substitute-path after empty rule removed"

gdb_test "unset substitute-path" \
         "" \
         "remove all remaining substitution rules"

gdb_test "show substitute-path" \
         "List of all source path substitution rules:" \
         "show substitute-path after all remaining rules removed"

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Andrew STUBBS]

Joel Brobecker wrote:
> I have added a first attempt at making a test. It only tests the
> manipulation of the list of substitution rules, but not the applying
> of them while debugging a program, because I am not sure how to do
> that without resorting to shell commands such as mkdir et al. It's
> still better than nothing, though.

How about two sets of sources with the same names, but different 
content. That way you can confirm that the alternate file is being read.

Andrew

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Andrew STUBBS]

Joel Brobecker wrote:
> +  /* If the list of rules are empty, then insert the new rule
> +     at the head of the list.  */
> +
> +  if (substitute_path_rules == NULL)
> +    {
> +      substitute_path_rules = rule;
> +      return;
> +    }
> +
> +  /* Otherwise, skip to the last rule in our list and then append
> +     the new rule.  */
> +
> +  last = substitute_path_rules;
> +  while (last->next != NULL)
> +    last = last->next;
> +
> +  last->next = rule;

What if the user tries to substitute the same path twice? I think it 
should delete the old rule (maybe query) and add the new one to the end.

> +  /* If no rule matching the argument was found, then print an error
> +     message to the user.  */
> +
> +  if (!rule_found)
> +    {
> +      if (from != NULL)
> +        error (_("No substitution rule defined for `%s'"), from);
> +      else
> +        error (_("No substitution rule defined"));

Is the latter case really an error? I would have thought not, since 
there's no way for a script to check the status before giving the command.

Andrew

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Joel Brobecker]

> >+  /* Otherwise, skip to the last rule in our list and then append
> >+     the new rule.  */
> >+
> >+  last = substitute_path_rules;
> >+  while (last->next != NULL)
> >+    last = last->next;
> >+
> >+  last->next = rule;
> 
> What if the user tries to substitute the same path twice? I think it 
> should delete the old rule (maybe query) and add the new one to the end.

I think we are getting dragged into over-engineering this feature.
If documentation is clear enough that it just adds, then he knows
he has to remove the previous rule before he introduces the new one.
That's plenty good enough in my opinion.

> >+  /* If no rule matching the argument was found, then print an error
> >+     message to the user.  */
> >+
> >+  if (!rule_found)
> >+    {
> >+      if (from != NULL)
> >+        error (_("No substitution rule defined for `%s'"), from);
> >+      else
> >+        error (_("No substitution rule defined"));
> 
> Is the latter case really an error? I would have thought not, since 
> there's no way for a script to check the status before giving the command.

I personally think so, but I don't have a strong opinion on this.
The error can be removed if this is the consensus.

-- 
Joel

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Daniel Jacobowitz]

On Mon, Jul 17, 2006 at 10:09:33AM -0700, Joel Brobecker wrote:
> > >+  /* Otherwise, skip to the last rule in our list and then append
> > >+     the new rule.  */
> > >+
> > >+  last = substitute_path_rules;
> > >+  while (last->next != NULL)
> > >+    last = last->next;
> > >+
> > >+  last->next = rule;
> > 
> > What if the user tries to substitute the same path twice? I think it 
> > should delete the old rule (maybe query) and add the new one to the end.
> 
> I think we are getting dragged into over-engineering this feature.
> If documentation is clear enough that it just adds, then he knows
> he has to remove the previous rule before he introduces the new one.
> That's plenty good enough in my opinion.

I'm inclined to agree with Andrew on both points he raised.

After that though, you're right - we're dragging this on too long.  If
you'll repost it with those two changes I will be sure to review it
today.

-- 
Daniel Jacobowitz
CodeSourcery

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Andrew STUBBS]

Joel Brobecker wrote:
>> What if the user tries to substitute the same path twice? I think it 
>> should delete the old rule (maybe query) and add the new one to the end.
> 
> I think we are getting dragged into over-engineering this feature.
> If documentation is clear enough that it just adds, then he knows
> he has to remove the previous rule before he introduces the new one.
> That's plenty good enough in my opinion.

I'm not sure that follows the principle of least surprise. You've 
already written the code to find and delete entries.

>> Is the latter case really an error? I would have thought not, since 
>> there's no way for a script to check the status before giving the command.
> 
> I personally think so, but I don't have a strong opinion on this.
> The error can be removed if this is the consensus.

I can just imagine myself having a script which deliberately clears the 
list, but then dies because it was already clear. FWIW, the 'directory' 
command does not complain if you try to reinitialise an empty source path.

(I suppose the workaround would be to define an arbitrary rule and then 
clear them all).

Andrew

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Joel Brobecker]

[-- Attachment #1: Type: text/plain, Size: 2704 bytes --]

Hello,

Sorry for the delay, got side-tracked on something else...

Here is take 3 of the substitute-path feature. I corrected something
that I forgot, namely use FILENAME_CMP to do comparisons rather than
strcmp. I also implemented Andrew's two suggestions.

2006-07-19  Joel Brobecker  <brobecker@adacore.com>

        * source.c: #include gdb_assert.h.
        (substitute_path_rule): New struct.
        (substitute_path_rules): New static global variable.
        (substitute_path_rule_matches): New function.
        (get_substitute_path_rule): New function.
        (rewrite_source_path): New function.
        (find_and_open_source): Add source path rewriting support.
        (strip_trailing_directory_separator): New function.
        (make_cleanup_argv): New function.
        (find_substitute_path_rule): New function.
        (add_substitute_path_rule): New function.
        (delete_substitute_path_rule): New function.
        (show_substitute_path_command): New function.
        (unset_substitute_path_command): New function.
        (set_substitute_path_command): New function.
        (_initialize_source): Add new substitute-path commands.
        * Makefile.in (source.o): Add dependency on gdb_assert.h.

Tested on x86-linux.

> 2006-07-14  Joel Brobecker  <brobecker@adacore.com>
> 
>         * gdb.base/subst.exp: New testcase.

I adjusted the testcase according to the modifications in the code.
I also tried to add a test that would verify that the substitution
correctly takes place, but as expected, I'm having some trouble
doing that. Here is what I did:

        * gdb.base/subst.exp
        * gdb.base/subst.c
        * gdb.base/subst.dir/subst.c

The version of subst.c in subst.dir is a modified version of subst.c.
I built the subst executable using gdb.base/subst.c, as usual. And then
tried to add a substitution rule as follow:

        (gdb) set substitute-path '${srcdir}/${subdir}' '${srcdir}/${subdir}/subst.dir'

But the problem is that ${srcdir} is not string equal to what compiler
put in the debugging information. As far as I can tell from the testcase
output, ${srcdir} is something like ../../gdb/testsuite. I don't see how
to reliably get the source path in a way that would be identical to what
the compiler sets.

Perhaps this is telling us that, instead of just FILENAME_CMP, we should
use something more sophisticated like xfullpath to check for path equality.
But I'm very reluctant to even suggest that, because performance would
probably become horrendous on large applications where lots and lots of
files are used.

Any suggestion on how to setup this test?

Again, documentation will be supplied as soon as this patch gets in.

Thanks,
-- 
Joel

[-- Attachment #2: subst.diff --]
[-- Type: text/plain, Size: 12841 bytes --]

Index: source.c
===================================================================
RCS file: /cvs/src/src/gdb/source.c,v
retrieving revision 1.75
diff -u -p -r1.75 source.c
--- source.c	15 May 2006 15:50:13 -0000	1.75
+++ source.c	19 Jul 2006 17:54:48 -0000
@@ -29,6 +29,7 @@
 #include "gdbcmd.h"
 #include "frame.h"
 #include "value.h"
+#include "gdb_assert.h"
 
 #include <sys/types.h>
 #include "gdb_string.h"
@@ -73,6 +74,17 @@ static void show_directories (char *, in
 
 char *source_path;
 
+/* Support for source path substitution commands.  */
+
+struct substitute_path_rule
+{
+  char *from;
+  char *to;
+  struct substitute_path_rule *next;
+};
+
+static struct substitute_path_rule *substitute_path_rules = NULL;
+
 /* Symtab of default file for listing lines of.  */
 
 static struct symtab *current_source_symtab;
@@ -828,6 +840,85 @@ source_full_path_of (char *filename, cha
   return 1;
 }
 
+/* Return non-zero if RULE matches PATH, that is if the rule can be
+   applied to PATH.  */
+
+static int
+substitute_path_rule_matches (const struct substitute_path_rule *rule,
+                              const char *path)
+{
+  const int from_len = strlen (rule->from);
+  const int path_len = strlen (path);
+  char *path_start;
+
+  if (path_len < from_len)
+    return 0;
+
+  /* The substitution rules are anchored at the start of the path,
+     so the path should start with rule->from.  There is no filename
+     comparison routine, so we need to extract the first FROM_LEN
+     characters from PATH first and use that to do the comparison.  */
+
+  path_start = alloca (from_len + 1);
+  strncpy (path_start, path, from_len);
+  path_start[from_len] = '\0';
+
+  if (FILENAME_CMP (path_start, rule->from) != 0)
+    return 0;
+
+  /* Make sure that the region in the path that matches the substitution
+     rule is immediately followed by a directory separator (or the end of
+     string character).  */
+  
+  if (path[from_len] != '\0' && !IS_DIR_SEPARATOR (path[from_len]))
+    return 0;
+
+  return 1;
+}
+
+/* Find the substitute-path rule that applies to PATH and return it.
+   Return NULL if no rule applies.  */
+
+static struct substitute_path_rule *
+get_substitute_path_rule (const char *path)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+
+  while (rule != NULL && !substitute_path_rule_matches (rule, path))
+    rule = rule->next;
+
+  return rule;
+}
+
+/* If the user specified a source path substitution rule that applies
+   to PATH, then apply it and return the new path.  This new path must
+   be deallocated afterwards.  
+   
+   Return NULL if no substitution rule was specified by the user,
+   or if no rule applied to the given PATH.  */
+   
+static char *
+rewrite_source_path (const char *path)
+{
+  const struct substitute_path_rule *rule = get_substitute_path_rule (path);
+  char *new_path;
+  int from_len;
+  
+  if (rule == NULL)
+    return NULL;
+
+  from_len = strlen (rule->from);
+
+  /* Compute the rewritten path and return it.  */
+
+  new_path =
+    (char *) xmalloc (strlen (path) + 1 + strlen (rule->to) - from_len);
+  strcpy (new_path, rule->to);
+  strcat (new_path, path + from_len);
+
+  return new_path;
+}
+
 /* This function is capable of finding the absolute path to a
    source file, and opening it, provided you give it an 
    OBJFILE and FILENAME. Both the DIRNAME and FULLNAME are only
@@ -844,7 +935,7 @@ source_full_path_of (char *filename, cha
      FULLNAME is set to the absolute path to the file just opened.
 
    On Failure
-     A non valid file descriptor is returned. ( the return value is negitive ) 
+     An invalid file descriptor is returned. ( the return value is negative ) 
      FULLNAME is set to NULL.  */
 int
 find_and_open_source (struct objfile *objfile,
@@ -857,8 +948,22 @@ find_and_open_source (struct objfile *ob
   int result;
 
   /* Quick way out if we already know its full name */
+
   if (*fullname)
     {
+      {
+        /* The user may have requested that source paths be rewritten
+           according to substitution rules he provided.  If a substitution
+           rule applies to this path, then apply it.  */
+        char *rewritten_fullname = rewrite_source_path (*fullname);
+
+        if (rewritten_fullname != NULL)
+           {
+             xfree (*fullname);
+             *fullname = rewritten_fullname;
+           }
+      }
+
       result = open (*fullname, OPEN_MODE);
       if (result >= 0)
 	return result;
@@ -869,6 +974,17 @@ find_and_open_source (struct objfile *ob
 
   if (dirname != NULL)
     {
+      /* If necessary, rewrite the compilation directory name according
+         to the source path substitution rules specified by the user.  */
+
+      char *rewritten_dirname = rewrite_source_path (dirname);
+
+      if (rewritten_dirname != NULL)
+        {
+          make_cleanup (xfree, rewritten_dirname);
+          dirname = rewritten_dirname;
+        }
+      
       /* Replace a path entry of  $cdir  with the compilation directory name */
 #define	cdir_len	5
       /* We cast strstr's result in case an ANSIhole has made it const,
@@ -1587,6 +1703,228 @@ reverse_search_command (char *regex, int
   fclose (stream);
   return;
 }
+
+/* If the last character of PATH is a directory separator, then strip it.  */
+
+static void
+strip_trailing_directory_separator (char *path)
+{
+  const int last = strlen (path) - 1;
+
+  if (last < 0)
+    return;  /* No stripping is needed if PATH is the empty string.  */
+
+  if (IS_DIR_SEPARATOR (path[last]))
+    path[last] = '\0';
+}
+
+/* A convenience function to push ARGV in the cleanup queue.  */
+
+static void
+make_cleanup_argv (char **argv)
+{
+  make_cleanup ((make_cleanup_ftype *) freeargv, argv);
+}
+
+/* Return the path substitution rule that matches FROM.
+   Return NULL if no rule matches.  */
+
+static struct substitute_path_rule *
+find_substitute_path_rule (const char *from)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+
+  while (rule != NULL)
+    {
+      if (FILENAME_CMP (rule->from, from) == 0)
+        return rule;
+      rule = rule->next;
+    }
+
+  return NULL;
+}
+
+/* Add a new substitute-path rule at the end of the current list of rules.
+   The new rule will replace FROM into TO.  */
+
+static void
+add_substitute_path_rule (char *from, char *to)
+{
+  struct substitute_path_rule *rule;
+  struct substitute_path_rule *new_rule;
+
+  new_rule = xmalloc (sizeof (struct substitute_path_rule));
+  new_rule->from = xstrdup (from);
+  new_rule->to = xstrdup (to);
+  new_rule->next = NULL;
+
+  /* If the list of rules are empty, then insert the new rule
+     at the head of the list.  */
+
+  if (substitute_path_rules == NULL)
+    {
+      substitute_path_rules = new_rule;
+      return;
+    }
+
+  /* Otherwise, skip to the last rule in our list and then append
+     the new rule.  */
+
+  rule = substitute_path_rules;
+  while (rule->next != NULL)
+    rule = rule->next;
+
+  rule->next = new_rule;
+}
+
+/* Remove the given source path substitution rule from the current list
+   of rules.  The memory allocated for that rule is also deallocated.  */
+
+static void
+delete_substitute_path_rule (struct substitute_path_rule *rule)
+{
+  if (rule == substitute_path_rules)
+    substitute_path_rules = rule->next;
+  else
+    {
+      struct substitute_path_rule *prev = substitute_path_rules;
+
+      while (prev != NULL && prev->next != rule)
+        prev = prev->next;
+
+      gdb_assert (prev != NULL);
+
+      prev->next = rule->next;
+    }
+
+  xfree (rule->from);
+  xfree (rule->to);
+  xfree (rule);
+}
+
+/* Implement the "show substitute-path" command.  */
+
+static void
+show_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv;
+  char *from = NULL;
+  
+  argv = buildargv (args);
+  make_cleanup_argv (argv);
+
+  /* We expect zero or one argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* Print the substitution rules.  */
+
+  if (from != NULL)
+    printf_filtered
+      (_("Source path substitution rule matching `%s':\n"), from);
+  else
+    printf_filtered (_("List of all source path substitution rules:\n"));
+
+  while (rule != NULL)
+    {
+      if (from == NULL || FILENAME_CMP (rule->from, from) == 0)
+        printf_filtered ("  `%s' -> `%s'.\n", rule->from, rule->to);
+      rule = rule->next;
+    }
+}
+
+/* Implement the "unset substitute-path" command.  */
+
+static void
+unset_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv = buildargv (args);
+  char *from = NULL;
+  int rule_found = 0;
+
+  /* This function takes either 0 or 1 argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* If the user asked for all the rules to be deleted, ask him
+     to confirm and give him a chance to abort before the action
+     is performed.  */
+
+  if (from == NULL
+      && !query (_("Delete all source path substitution rules? ")))
+    error (_("Canceled"));
+
+  /* Delete the rule matching the argument.  No argument means that
+     all rules should be deleted.  */
+
+  while (rule != NULL)
+    {
+      struct substitute_path_rule *next = rule->next;
+
+      if (from == NULL || FILENAME_CMP (from, rule->from) == 0)
+        {
+          delete_substitute_path_rule (rule);
+          rule_found = 1;
+        }
+
+      rule = next;
+    }
+  
+  /* If the user asked for a specific rule to be deleted but
+     we could not find it, then report an error.  */
+
+  if (from != NULL && !rule_found)
+    error (_("No substitution rule defined for `%s'"), from);
+}
+
+/* Add a new source path substitution rule.  */
+
+static void
+set_substitute_path_command (char *args, int from_tty)
+{
+  char *from_path, *to_path;
+  char **argv;
+  struct substitute_path_rule *rule;
+  
+  argv = buildargv (args);
+  make_cleanup_argv (argv);
+
+  if (argv == NULL || argv[0] == NULL || argv [1] == NULL)
+    error (_("Incorrect usage, too few arguments in command"));
+
+  if (argv[2] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (*(argv[0]) == '\0')
+    error (_("First argument must be at least one character long"));
+
+  /* Strip any trailing directory separator character in either FROM
+     or TO.  The substitution rule already implicitly contains them.  */
+  strip_trailing_directory_separator (argv[0]);
+  strip_trailing_directory_separator (argv[1]);
+
+  /* If a rule with the same "from" was previously defined, then
+     delete it.  This new rule replaces it.  */
+
+  rule = find_substitute_path_rule (argv[0]);
+  if (rule != NULL)
+    delete_substitute_path_rule (rule);
+      
+  /* Insert the new substitution rule.  */
+
+  add_substitute_path_rule (argv[0], argv[1]);
+}
+
 \f
 void
 _initialize_source (void)
@@ -1666,4 +2004,19 @@ Show number of source lines gdb will lis
 			    NULL,
 			    show_lines_to_list,
 			    &setlist, &showlist);
+
+  add_cmd ("substitute-path", class_files, set_substitute_path_command,
+           _("\
+Add a source path substitution rule.  If a substitution rule was previously\n\
+set, it is overridden."), &setlist);
+
+  add_cmd ("substitute-path", class_files, unset_substitute_path_command,
+           _("\
+Remove the current source path substitution rule.  This has no effect\n\
+if no path substitution rule was previously specified."),
+           &unsetlist);
+
+  add_cmd ("substitute-path", class_files, show_substitute_path_command,
+           _("Show the current source path substitution rule."),
+           &showlist);
 }
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.822
diff -u -p -r1.822 Makefile.in
--- Makefile.in	23 Jun 2006 13:01:05 -0000	1.822
+++ Makefile.in	19 Jul 2006 17:54:49 -0000
@@ -2630,7 +2630,8 @@ source.o: source.c $(defs_h) $(symtab_h)
 	$(command_h) $(source_h) $(gdbcmd_h) $(frame_h) $(value_h) \
 	$(gdb_string_h) $(gdb_stat_h) $(gdbcore_h) $(gdb_regex_h) \
 	$(symfile_h) $(objfiles_h) $(annotate_h) $(gdbtypes_h) $(linespec_h) \
-	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h)
+	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h) \
+	$(gdb_assert_h)
 sparc64fbsd-nat.o: sparc64fbsd-nat.c $(defs_h) $(regcache_h) $(target_h) \
 	$(fbsd_nat_h) $(sparc64_tdep_h) $(sparc_nat_h) $(bsd_kvm_h)
 sparc64fbsd-tdep.o: sparc64fbsd-tdep.c $(defs_h) $(frame_h) \

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Daniel Jacobowitz]

On Wed, Jul 19, 2006 at 11:15:16AM -0700, Joel Brobecker wrote:
> I adjusted the testcase according to the modifications in the code.
> I also tried to add a test that would verify that the substitution
> correctly takes place, but as expected, I'm having some trouble
> doing that. Here is what I did:
> 
>         * gdb.base/subst.exp
>         * gdb.base/subst.c
>         * gdb.base/subst.dir/subst.c
> 
> The version of subst.c in subst.dir is a modified version of subst.c.
> I built the subst executable using gdb.base/subst.c, as usual. And then
> tried to add a substitution rule as follow:
> 
>         (gdb) set substitute-path '${srcdir}/${subdir}' '${srcdir}/${subdir}/subst.dir'
> 
> But the problem is that ${srcdir} is not string equal to what compiler
> put in the debugging information. As far as I can tell from the testcase
> output, ${srcdir} is something like ../../gdb/testsuite. I don't see how
> to reliably get the source path in a way that would be identical to what
> the compiler sets.
> 
> Perhaps this is telling us that, instead of just FILENAME_CMP, we should
> use something more sophisticated like xfullpath to check for path equality.
> But I'm very reluctant to even suggest that, because performance would
> probably become horrendous on large applications where lots and lots of
> files are used.

Let's not go towards xfullpath for this please.  The whole problem is
that we don't want to rely on build-time paths if told not to; we
shouldn't be affected by what's on the disk now.

The best way to handle this is to ask the compiler.  Try loading the
binary and running "info source"; it will print out the compilation
directory.

>    /* Quick way out if we already know its full name */
> +
>    if (*fullname)
>      {
> +      {
> +        /* The user may have requested that source paths be rewritten
> +           according to substitution rules he provided.  If a substitution
> +           rule applies to this path, then apply it.  */
> +        char *rewritten_fullname = rewrite_source_path (*fullname);
> +
> +        if (rewritten_fullname != NULL)
> +           {
> +             xfree (*fullname);
> +             *fullname = rewritten_fullname;
> +           }
> +      }
> +
>        result = open (*fullname, OPEN_MODE);
>        if (result >= 0)
>  	return result;

You don't need the extra { } here.

> +/* If the last character of PATH is a directory separator, then strip it.  */
> +
> +static void
> +strip_trailing_directory_separator (char *path)
> +{
> +  const int last = strlen (path) - 1;
> +
> +  if (last < 0)
> +    return;  /* No stripping is needed if PATH is the empty string.  */
> +
> +  if (IS_DIR_SEPARATOR (path[last]))
> +    path[last] = '\0';
> +}

Is this going to get you in trouble if PATH is "/" ?  I can imagine
that happening.

> +/* A convenience function to push ARGV in the cleanup queue.  */
> +
> +static void
> +make_cleanup_argv (char **argv)
> +{
> +  make_cleanup ((make_cleanup_ftype *) freeargv, argv);
> +}

Casting function types is a good way to get in trouble.  In this case,
there's an answer handy: make_cleanup_freeargv.


Otherwise looks great!

-- 
Daniel Jacobowitz
CodeSourcery

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Joel Brobecker]

[-- Attachment #1: Type: text/plain, Size: 3235 bytes --]

> >    /* Quick way out if we already know its full name */
> > +
> >    if (*fullname)
> >      {
> > +      {
> > +        /* The user may have requested that source paths be rewritten
> > +           according to substitution rules he provided.  If a substitution
> > +           rule applies to this path, then apply it.  */
> > +        char *rewritten_fullname = rewrite_source_path (*fullname);
> > +
> > +        if (rewritten_fullname != NULL)
> > +           {
> > +             xfree (*fullname);
> > +             *fullname = rewritten_fullname;
> > +           }
> > +      }
> > +
> >        result = open (*fullname, OPEN_MODE);
> >        if (result >= 0)
> >  	return result;
> 
> You don't need the extra { } here.

OK. I used them to reduce the scope of rewritten_fullname to where
this variable is actually used, but I can see that it's not very useful.

> > +/* If the last character of PATH is a directory separator, then strip it.  */
> > +
> > +static void
> > +strip_trailing_directory_separator (char *path)
> > +{
> > +  const int last = strlen (path) - 1;
> > +
> > +  if (last < 0)
> > +    return;  /* No stripping is needed if PATH is the empty string.  */
> > +
> > +  if (IS_DIR_SEPARATOR (path[last]))
> > +    path[last] = '\0';
> > +}
> 
> Is this going to get you in trouble if PATH is "/" ?  I can imagine
> that happening.

I do not think so. In terms of the function itself, no problem, this
is reduced to the empty string. In terms of where we do the matching,
the function will correctly match anything that starts with '/', and
nothing else. I also verified that it's possible to remove that
substitution rule using the emtpy string.

However, you might prefer us to adjust the UI a bit, and still keep
the '/' at the UI level. So add some tweaks to "show substitute-path"
and "unset substitute-path" that will handle '/' as well as ''.

So instead of having "show sub" print `' -> `/mnt', it will print
`/' -> `/mnt'. And "unset sub" will accept both '' and '/' as argument
to delete that rule. It seems hardly necessary, but I don't mind adding
this (and the corresponding tests in subst.exp).

> Casting function types is a good way to get in trouble.  In this case,
> there's an answer handy: make_cleanup_freeargv.

How conveninent, thanks! Adjusted accordingly.

        * source.c: #include gdb_assert.h.
        (substitute_path_rule): New struct.
        (substitute_path_rules): New static global variable.
        (substitute_path_rule_matches): New function.
        (get_substitute_path_rule): New function.
        (rewrite_source_path): New function.
        (find_and_open_source): Add source path rewriting support.
        (strip_trailing_directory_separator): New function.
        (find_substitute_path_rule): New function.
        (add_substitute_path_rule): New function.
        (delete_substitute_path_rule): New function.
        (show_substitute_path_command): New function.
        (unset_substitute_path_command): New function.
        (set_substitute_path_command): New function.
        (_initialize_source): Add new substitute-path commands.
        * Makefile.in (source.o): Add dependency on gdb_assert.h.

Does it look better? Tested on x86-linux.

-- 
Joel

[-- Attachment #2: subst.diff --]
[-- Type: text/plain, Size: 12630 bytes --]

Index: source.c
===================================================================
RCS file: /cvs/src/src/gdb/source.c,v
retrieving revision 1.75
diff -u -p -r1.75 source.c
--- source.c	15 May 2006 15:50:13 -0000	1.75
+++ source.c	25 Jul 2006 16:01:19 -0000
@@ -29,6 +29,7 @@
 #include "gdbcmd.h"
 #include "frame.h"
 #include "value.h"
+#include "gdb_assert.h"
 
 #include <sys/types.h>
 #include "gdb_string.h"
@@ -73,6 +74,17 @@ static void show_directories (char *, in
 
 char *source_path;
 
+/* Support for source path substitution commands.  */
+
+struct substitute_path_rule
+{
+  char *from;
+  char *to;
+  struct substitute_path_rule *next;
+};
+
+static struct substitute_path_rule *substitute_path_rules = NULL;
+
 /* Symtab of default file for listing lines of.  */
 
 static struct symtab *current_source_symtab;
@@ -828,6 +840,85 @@ source_full_path_of (char *filename, cha
   return 1;
 }
 
+/* Return non-zero if RULE matches PATH, that is if the rule can be
+   applied to PATH.  */
+
+static int
+substitute_path_rule_matches (const struct substitute_path_rule *rule,
+                              const char *path)
+{
+  const int from_len = strlen (rule->from);
+  const int path_len = strlen (path);
+  char *path_start;
+
+  if (path_len < from_len)
+    return 0;
+
+  /* The substitution rules are anchored at the start of the path,
+     so the path should start with rule->from.  There is no filename
+     comparison routine, so we need to extract the first FROM_LEN
+     characters from PATH first and use that to do the comparison.  */
+
+  path_start = alloca (from_len + 1);
+  strncpy (path_start, path, from_len);
+  path_start[from_len] = '\0';
+
+  if (FILENAME_CMP (path_start, rule->from) != 0)
+    return 0;
+
+  /* Make sure that the region in the path that matches the substitution
+     rule is immediately followed by a directory separator (or the end of
+     string character).  */
+  
+  if (path[from_len] != '\0' && !IS_DIR_SEPARATOR (path[from_len]))
+    return 0;
+
+  return 1;
+}
+
+/* Find the substitute-path rule that applies to PATH and return it.
+   Return NULL if no rule applies.  */
+
+static struct substitute_path_rule *
+get_substitute_path_rule (const char *path)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+
+  while (rule != NULL && !substitute_path_rule_matches (rule, path))
+    rule = rule->next;
+
+  return rule;
+}
+
+/* If the user specified a source path substitution rule that applies
+   to PATH, then apply it and return the new path.  This new path must
+   be deallocated afterwards.  
+   
+   Return NULL if no substitution rule was specified by the user,
+   or if no rule applied to the given PATH.  */
+   
+static char *
+rewrite_source_path (const char *path)
+{
+  const struct substitute_path_rule *rule = get_substitute_path_rule (path);
+  char *new_path;
+  int from_len;
+  
+  if (rule == NULL)
+    return NULL;
+
+  from_len = strlen (rule->from);
+
+  /* Compute the rewritten path and return it.  */
+
+  new_path =
+    (char *) xmalloc (strlen (path) + 1 + strlen (rule->to) - from_len);
+  strcpy (new_path, rule->to);
+  strcat (new_path, path + from_len);
+
+  return new_path;
+}
+
 /* This function is capable of finding the absolute path to a
    source file, and opening it, provided you give it an 
    OBJFILE and FILENAME. Both the DIRNAME and FULLNAME are only
@@ -844,7 +935,7 @@ source_full_path_of (char *filename, cha
      FULLNAME is set to the absolute path to the file just opened.
 
    On Failure
-     A non valid file descriptor is returned. ( the return value is negitive ) 
+     An invalid file descriptor is returned. ( the return value is negative ) 
      FULLNAME is set to NULL.  */
 int
 find_and_open_source (struct objfile *objfile,
@@ -857,8 +948,20 @@ find_and_open_source (struct objfile *ob
   int result;
 
   /* Quick way out if we already know its full name */
+
   if (*fullname)
     {
+      /* The user may have requested that source paths be rewritten
+         according to substitution rules he provided.  If a substitution
+         rule applies to this path, then apply it.  */
+      char *rewritten_fullname = rewrite_source_path (*fullname);
+
+      if (rewritten_fullname != NULL)
+        {
+          xfree (*fullname);
+          *fullname = rewritten_fullname;
+        }
+
       result = open (*fullname, OPEN_MODE);
       if (result >= 0)
 	return result;
@@ -869,6 +972,17 @@ find_and_open_source (struct objfile *ob
 
   if (dirname != NULL)
     {
+      /* If necessary, rewrite the compilation directory name according
+         to the source path substitution rules specified by the user.  */
+
+      char *rewritten_dirname = rewrite_source_path (dirname);
+
+      if (rewritten_dirname != NULL)
+        {
+          make_cleanup (xfree, rewritten_dirname);
+          dirname = rewritten_dirname;
+        }
+      
       /* Replace a path entry of  $cdir  with the compilation directory name */
 #define	cdir_len	5
       /* We cast strstr's result in case an ANSIhole has made it const,
@@ -1587,6 +1701,220 @@ reverse_search_command (char *regex, int
   fclose (stream);
   return;
 }
+
+/* If the last character of PATH is a directory separator, then strip it.  */
+
+static void
+strip_trailing_directory_separator (char *path)
+{
+  const int last = strlen (path) - 1;
+
+  if (last < 0)
+    return;  /* No stripping is needed if PATH is the empty string.  */
+
+  if (IS_DIR_SEPARATOR (path[last]))
+    path[last] = '\0';
+}
+
+/* Return the path substitution rule that matches FROM.
+   Return NULL if no rule matches.  */
+
+static struct substitute_path_rule *
+find_substitute_path_rule (const char *from)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+
+  while (rule != NULL)
+    {
+      if (FILENAME_CMP (rule->from, from) == 0)
+        return rule;
+      rule = rule->next;
+    }
+
+  return NULL;
+}
+
+/* Add a new substitute-path rule at the end of the current list of rules.
+   The new rule will replace FROM into TO.  */
+
+static void
+add_substitute_path_rule (char *from, char *to)
+{
+  struct substitute_path_rule *rule;
+  struct substitute_path_rule *new_rule;
+
+  new_rule = xmalloc (sizeof (struct substitute_path_rule));
+  new_rule->from = xstrdup (from);
+  new_rule->to = xstrdup (to);
+  new_rule->next = NULL;
+
+  /* If the list of rules are empty, then insert the new rule
+     at the head of the list.  */
+
+  if (substitute_path_rules == NULL)
+    {
+      substitute_path_rules = new_rule;
+      return;
+    }
+
+  /* Otherwise, skip to the last rule in our list and then append
+     the new rule.  */
+
+  rule = substitute_path_rules;
+  while (rule->next != NULL)
+    rule = rule->next;
+
+  rule->next = new_rule;
+}
+
+/* Remove the given source path substitution rule from the current list
+   of rules.  The memory allocated for that rule is also deallocated.  */
+
+static void
+delete_substitute_path_rule (struct substitute_path_rule *rule)
+{
+  if (rule == substitute_path_rules)
+    substitute_path_rules = rule->next;
+  else
+    {
+      struct substitute_path_rule *prev = substitute_path_rules;
+
+      while (prev != NULL && prev->next != rule)
+        prev = prev->next;
+
+      gdb_assert (prev != NULL);
+
+      prev->next = rule->next;
+    }
+
+  xfree (rule->from);
+  xfree (rule->to);
+  xfree (rule);
+}
+
+/* Implement the "show substitute-path" command.  */
+
+static void
+show_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv;
+  char *from = NULL;
+  
+  argv = buildargv (args);
+  make_cleanup_freeargv (argv);
+
+  /* We expect zero or one argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* Print the substitution rules.  */
+
+  if (from != NULL)
+    printf_filtered
+      (_("Source path substitution rule matching `%s':\n"), from);
+  else
+    printf_filtered (_("List of all source path substitution rules:\n"));
+
+  while (rule != NULL)
+    {
+      if (from == NULL || FILENAME_CMP (rule->from, from) == 0)
+        printf_filtered ("  `%s' -> `%s'.\n", rule->from, rule->to);
+      rule = rule->next;
+    }
+}
+
+/* Implement the "unset substitute-path" command.  */
+
+static void
+unset_substitute_path_command (char *args, int from_tty)
+{
+  struct substitute_path_rule *rule = substitute_path_rules;
+  char **argv = buildargv (args);
+  char *from = NULL;
+  int rule_found = 0;
+
+  /* This function takes either 0 or 1 argument.  */
+
+  if (argv != NULL && argv[0] != NULL && argv[1] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (argv != NULL && argv[0] != NULL)
+    from = argv[0];
+
+  /* If the user asked for all the rules to be deleted, ask him
+     to confirm and give him a chance to abort before the action
+     is performed.  */
+
+  if (from == NULL
+      && !query (_("Delete all source path substitution rules? ")))
+    error (_("Canceled"));
+
+  /* Delete the rule matching the argument.  No argument means that
+     all rules should be deleted.  */
+
+  while (rule != NULL)
+    {
+      struct substitute_path_rule *next = rule->next;
+
+      if (from == NULL || FILENAME_CMP (from, rule->from) == 0)
+        {
+          delete_substitute_path_rule (rule);
+          rule_found = 1;
+        }
+
+      rule = next;
+    }
+  
+  /* If the user asked for a specific rule to be deleted but
+     we could not find it, then report an error.  */
+
+  if (from != NULL && !rule_found)
+    error (_("No substitution rule defined for `%s'"), from);
+}
+
+/* Add a new source path substitution rule.  */
+
+static void
+set_substitute_path_command (char *args, int from_tty)
+{
+  char *from_path, *to_path;
+  char **argv;
+  struct substitute_path_rule *rule;
+  
+  argv = buildargv (args);
+  make_cleanup_freeargv (argv);
+
+  if (argv == NULL || argv[0] == NULL || argv [1] == NULL)
+    error (_("Incorrect usage, too few arguments in command"));
+
+  if (argv[2] != NULL)
+    error (_("Incorrect usage, too many arguments in command"));
+
+  if (*(argv[0]) == '\0')
+    error (_("First argument must be at least one character long"));
+
+  /* Strip any trailing directory separator character in either FROM
+     or TO.  The substitution rule already implicitly contains them.  */
+  strip_trailing_directory_separator (argv[0]);
+  strip_trailing_directory_separator (argv[1]);
+
+  /* If a rule with the same "from" was previously defined, then
+     delete it.  This new rule replaces it.  */
+
+  rule = find_substitute_path_rule (argv[0]);
+  if (rule != NULL)
+    delete_substitute_path_rule (rule);
+      
+  /* Insert the new substitution rule.  */
+
+  add_substitute_path_rule (argv[0], argv[1]);
+}
+
 \f
 void
 _initialize_source (void)
@@ -1666,4 +1994,19 @@ Show number of source lines gdb will lis
 			    NULL,
 			    show_lines_to_list,
 			    &setlist, &showlist);
+
+  add_cmd ("substitute-path", class_files, set_substitute_path_command,
+           _("\
+Add a source path substitution rule.  If a substitution rule was previously\n\
+set, it is overridden."), &setlist);
+
+  add_cmd ("substitute-path", class_files, unset_substitute_path_command,
+           _("\
+Remove the current source path substitution rule.  This has no effect\n\
+if no path substitution rule was previously specified."),
+           &unsetlist);
+
+  add_cmd ("substitute-path", class_files, show_substitute_path_command,
+           _("Show the current source path substitution rule."),
+           &showlist);
 }
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.822
diff -u -p -r1.822 Makefile.in
--- Makefile.in	23 Jun 2006 13:01:05 -0000	1.822
+++ Makefile.in	25 Jul 2006 16:01:21 -0000
@@ -2630,7 +2630,8 @@ source.o: source.c $(defs_h) $(symtab_h)
 	$(command_h) $(source_h) $(gdbcmd_h) $(frame_h) $(value_h) \
 	$(gdb_string_h) $(gdb_stat_h) $(gdbcore_h) $(gdb_regex_h) \
 	$(symfile_h) $(objfiles_h) $(annotate_h) $(gdbtypes_h) $(linespec_h) \
-	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h)
+	$(filenames_h) $(completer_h) $(ui_out_h) $(readline_h) \
+	$(gdb_assert_h)
 sparc64fbsd-nat.o: sparc64fbsd-nat.c $(defs_h) $(regcache_h) $(target_h) \
 	$(fbsd_nat_h) $(sparc64_tdep_h) $(sparc_nat_h) $(bsd_kvm_h)
 sparc64fbsd-tdep.o: sparc64fbsd-tdep.c $(defs_h) $(frame_h) \

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Daniel Jacobowitz]

On Tue, Jul 25, 2006 at 09:28:29AM -0700, Joel Brobecker wrote:
>         * source.c: #include gdb_assert.h.
>         (substitute_path_rule): New struct.
>         (substitute_path_rules): New static global variable.
>         (substitute_path_rule_matches): New function.
>         (get_substitute_path_rule): New function.
>         (rewrite_source_path): New function.
>         (find_and_open_source): Add source path rewriting support.
>         (strip_trailing_directory_separator): New function.
>         (find_substitute_path_rule): New function.
>         (add_substitute_path_rule): New function.
>         (delete_substitute_path_rule): New function.
>         (show_substitute_path_command): New function.
>         (unset_substitute_path_command): New function.
>         (set_substitute_path_command): New function.
>         (_initialize_source): Add new substitute-path commands.
>         * Makefile.in (source.o): Add dependency on gdb_assert.h.
> 
> Does it look better? Tested on x86-linux.

OK.  Let's go with this version.  It needs documentation, testcase, and
probably NEWS; those can be next :-)

Thanks!  Feel free to commit.

-- 
Daniel Jacobowitz
CodeSourcery

Re: [RFA] set/unset/show substitute-path commands (take 2)

[Joel Brobecker]

> On Tue, Jul 25, 2006 at 09:28:29AM -0700, Joel Brobecker wrote:
> >         * source.c: #include gdb_assert.h.
> >         (substitute_path_rule): New struct.
> >         (substitute_path_rules): New static global variable.
> >         (substitute_path_rule_matches): New function.
> >         (get_substitute_path_rule): New function.
> >         (rewrite_source_path): New function.
> >         (find_and_open_source): Add source path rewriting support.
> >         (strip_trailing_directory_separator): New function.
> >         (find_substitute_path_rule): New function.
> >         (add_substitute_path_rule): New function.
> >         (delete_substitute_path_rule): New function.
> >         (show_substitute_path_command): New function.
> >         (unset_substitute_path_command): New function.
> >         (set_substitute_path_command): New function.
> >         (_initialize_source): Add new substitute-path commands.
> >         * Makefile.in (source.o): Add dependency on gdb_assert.h.
> > 
> > Does it look better? Tested on x86-linux.
> 
> OK.  Let's go with this version.  It needs documentation, testcase, and
> probably NEWS; those can be next :-)
> 
> Thanks!  Feel free to commit.

Now checked in - same for the doco part. NEWS entry next...

-- 
Joel