[PATCH v3 2/2] MI: Add new command -complete

[Jan Vrany <jan.vrany@fit.cvut.cz>]

There is a CLI command 'complete' intended to use with emacs. Such a command
would also be useful for MI frontends, when separate CLI and MI channels cannot
be used. For example, on Windows (because of lack of PTYs) or when GDB is used
through SSH session.

This commit adds a new '-complete' MI command.

gdb/Changelog:
2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>

	* mi/mi-cmds.h (mi_cmd_complete): New function.
	* mi/mi-main.c (mi_cmd_complete): Likewise.
	* mi/mi-cmds.c: Define new MI command -complete.
	* NEWS: Mention new -complete command.

gdb/doc/ChangeLog:
2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>

	* gdb.texinfo (Miscellaneous GDB/MI Commands): Document new
	MI command -complete.

gdb/testsuite/ChangeLog:
2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>

	* gdb.mi/mi-complete.exp: New file.
	* gdb.mi/mi-complete.cc: Likewise.
---
 gdb/ChangeLog                        |  7 +++
 gdb/NEWS                             |  7 +++
 gdb/doc/ChangeLog                    |  5 ++
 gdb/doc/gdb.texinfo                  | 57 +++++++++++++++++++++
 gdb/mi/mi-cmds.c                     |  2 +
 gdb/mi/mi-cmds.h                     |  1 +
 gdb/mi/mi-main.c                     | 49 ++++++++++++++++++
 gdb/testsuite/ChangeLog              |  5 ++
 gdb/testsuite/gdb.mi/mi-complete.cc  | 21 ++++++++
 gdb/testsuite/gdb.mi/mi-complete.exp | 75 ++++++++++++++++++++++++++++
 10 files changed, 229 insertions(+)
 create mode 100644 gdb/testsuite/gdb.mi/mi-complete.cc
 create mode 100644 gdb/testsuite/gdb.mi/mi-complete.exp

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index be65f4a2d6..9865bbbf4d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* mi/mi-cmds.h (mi_cmd_complete): New function.
+	* mi/mi-main.c (mi_cmd_complete): Likewise.
+	* mi/mi-cmds.c: Define new MI command -complete.
+	* NEWS: Mention new -complete command.
+
 2019-01-24  Jan Vrany  <jan.vrany@fit.cvut.cz>
 
 	* completer.h (complete): New function.
diff --git a/gdb/NEWS b/gdb/NEWS
index eaef6aa384..3018313a46 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -96,6 +96,13 @@ maint show dwarf unwinders
 info proc files
   Display a list of open files for a process.
 
+* New MI commands
+
+-complete
+  This lists all the possible completions for the rest of the line, if it
+  were to be given as a command itself.  This is intended for use by MI frontends
+  in cases when separate CLI and MI channels cannot be used.
+
 * Changed commands
 
 Changes to the "frame", "select-frame", and "info frame" CLI commands.
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index d38d4625c4..669f7e8ce6 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* gdb.texinfo (Miscellaneous GDB/MI Commands): Document new
+	MI command -complete.
+
 2019-01-16  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* gdb.texinfo (GDB/MI Development and Front Ends): Add table of
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 173d18be6f..dff181dc2d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -34317,6 +34317,63 @@ fullname="/home/nickrob/myprog.c",line="73",arch="i386:x86_64"@}
 (gdb)
 @end smallexample
 
+@subheading The @code{-complete} Command
+@findex -complete
+
+@subheading Synopsis
+
+@smallexample
+-complete @var{command}
+@end smallexample
+
+Show a list of completions for partially typed CLI @var{command}.
+
+This command is intended for @sc{gdb/mi} frontends that cannot use two separate
+CLI and MI channels - for example: because of lack of PTYs like on Windows or
+because @sc{gdb} is used remotely via a SSH connection.
+
+@subheading Result
+
+The result consists of two one or two fields:
+
+@table @samp
+@item completion
+This field contain a string to be completed on a command line, including
+@var{command} passed as parameter to @code{-complete} command. If nothing can
+be completed this field is omitted.
+
+@item matches
+This field contain (possibly empty) array of matches. It is always present.
+
+@end table
+
+@subheading @value{GDBN} Command
+
+The corresponding @value{GDBN} command is @samp{complete}.
+
+@subheading Example
+
+@smallexample
+(gdb)
+-complete br
+^done,completion="break",matches=["break","break-range"],max_completions_reached="0"
+(gdb)
+-complete "b ma"
+^done,completion="b ma",matches=["b madvise","b main"],max_completions_reached="0"
+(gdb)
+-complete "b push_b"
+^done,completion="b push_back(",
+      matches=["b A::push_back(void*)",
+               "b std::string::push_back(char)",
+               "b std::vector<int, std::allocator<int> >::push_back(int&&)"],
+      max_completions_reached="0"
+(gdb)
+-complete "nonexist"
+^done,matches=[],max_completions_reached="0"
+(gdb)
+
+@end smallexample
+
 @node Annotations
 @chapter @value{GDBN} Annotations
 
diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
index bb7c20c777..683e990cdf 100644
--- a/gdb/mi/mi-cmds.c
+++ b/gdb/mi/mi-cmds.c
@@ -23,6 +23,7 @@
 #include "mi-cmds.h"
 #include "mi-main.h"
 
+
 struct mi_cmd;
 static struct mi_cmd **lookup_table (const char *command);
 static void build_table (struct mi_cmd *commands);
@@ -75,6 +76,7 @@ static struct mi_cmd mi_cmds[] =
                    &mi_suppress_notification.breakpoint),
   DEF_MI_CMD_MI_1 ("catch-unload", mi_cmd_catch_unload,
                    &mi_suppress_notification.breakpoint),
+  DEF_MI_CMD_MI ("complete", mi_cmd_complete),
   DEF_MI_CMD_MI ("data-disassemble", mi_cmd_disassemble),
   DEF_MI_CMD_MI ("data-evaluate-expression", mi_cmd_data_evaluate_expression),
   DEF_MI_CMD_MI ("data-list-changed-registers",
diff --git a/gdb/mi/mi-cmds.h b/gdb/mi/mi-cmds.h
index af38363cfc..32bd747d43 100644
--- a/gdb/mi/mi-cmds.h
+++ b/gdb/mi/mi-cmds.h
@@ -125,6 +125,7 @@ extern mi_cmd_argv_ftype mi_cmd_var_update;
 extern mi_cmd_argv_ftype mi_cmd_enable_pretty_printing;
 extern mi_cmd_argv_ftype mi_cmd_enable_frame_filters;
 extern mi_cmd_argv_ftype mi_cmd_var_set_update_range;
+extern mi_cmd_argv_ftype mi_cmd_complete;
 
 /* Description of a single command.  */
 
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 7176963845..d6ddfea78d 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -2709,6 +2709,55 @@ mi_cmd_trace_frame_collected (const char *command, char **argv, int argc)
   }
 }
 
+/* Implement the "-complete" command.  */
+
+void
+mi_cmd_complete (const char *command, char **argv, int argc)
+{
+  if (argc != 1)
+    {
+      error (_("Usage: -complete COMMAND"));
+    }
+  if (max_completions == 0)
+    {
+      error (_("max-completions is zero,"
+               " completion is disabled.\n"));
+    }
+
+  int quote_char = '\0';
+  const char *word;
+
+  completion_result result = complete (argv[0], &word, &quote_char);
+
+  std::string arg_prefix (argv[0], word - argv[0]);
+
+  struct ui_out *uiout = current_uiout;
+
+  if (result.number_matches > 0)
+    uiout->field_fmt ("completion", "%s%s", arg_prefix.c_str (), result.match_list[0]);
+
+  {
+    ui_out_emit_list completions_emitter (uiout, "matches");
+
+    if (result.number_matches == 1)
+      {
+        uiout->field_fmt(NULL, "%s%s", arg_prefix.c_str (), result.match_list[0]);
+      }
+    else
+      {
+        result.sort_match_list ();
+        for (size_t i = 0; i < result.number_matches; i++)
+          {
+            uiout->field_fmt(NULL, "%s%s", arg_prefix.c_str (),
+                                           result.match_list[i + 1]);
+          }
+      }
+  }
+  uiout->field_string ("max_completions_reached",
+                       result.number_matches == max_completions ? "1" : "0");
+}
+
+
 void
 _initialize_mi_main (void)
 {
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 7d8c7908fe..03135837f8 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* gdb.mi/mi-complete.exp: New file.
+	* gdb.mi/mi-complete.cc: Likewise.
+
 2019-01-21  Alan Hayward  <alan.hayward@arm.com>
 	* gdb.base/infcall-nested-structs.exp: Test C++ in addition to C.
 
diff --git a/gdb/testsuite/gdb.mi/mi-complete.cc b/gdb/testsuite/gdb.mi/mi-complete.cc
new file mode 100644
index 0000000000..fc85057d69
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-complete.cc
@@ -0,0 +1,21 @@
+#include <vector>
+
+class A
+{
+public:
+  void push_back(void *value);
+};
+
+void A::push_back(void *value)
+{
+  /* nothing */
+}
+
+int main(int argc, char **argv)
+{
+    std::vector<int> v;
+    v.push_back(1);
+    A a;
+    a.push_back(&v);
+    return 0;
+}
\ No newline at end of file
diff --git a/gdb/testsuite/gdb.mi/mi-complete.exp b/gdb/testsuite/gdb.mi/mi-complete.exp
new file mode 100644
index 0000000000..e82c2bff40
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-complete.exp
@@ -0,0 +1,75 @@
+# Copyright 2018 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# Verify -data-evaluate-expression. There are really minimal tests.
+
+# The goal is not to test gdb functionality, which is done by other tests,
+# but to verify the correct output response to MI operations.
+#
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+gdb_exit
+if [mi_gdb_start] {
+    continue
+}
+
+standard_testfile .cc
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
+     untested "failed to compile"
+     return -1
+}
+
+mi_run_to_main
+
+mi_gdb_test "1-complete br" \
+            "1\\^done,completion=\"break\",matches=\\\[.*\"break\",.*\"break-range\".*\\\],max_completions_reached=\"0\"" \
+            "-complete br"
+
+# Check empty completion list
+mi_gdb_test "5-complete bogus" \
+            "5\\^done,matches=\\\[\\\],max_completions_reached=\"0\"" \
+            "-complete bogus"
+
+# Check completions for commands with space
+mi_gdb_test "4-complete \"b mai\"" \
+            "4\\^done,completion=\"b main\",matches=\\\[.*\"b main\".*\\\],max_completions_reached=\"0\"" \
+            "-complete \"b mai\""
+
+# Check wildmatching
+mi_gdb_test "5-complete \"b push_ba\"" \
+            "5\\^done,completion=\"b push_back\\(\",matches=\\\[.*\"b A::push_back\\(void\\*\\)\".*\\\],max_completions_reached=\"0\"" \
+            "-complete \"b push_ba\" (wildmatching)"
+
+mi_gdb_test "-info-gdb-mi-command complete" \
+            "\\^done,command=\{exists=\"true\"\}" \
+            "-info-gdb-mi-command complete"
+
+# Limit max completions and check that max_completions_reached=\"0\" is set
+# to 1.
+send_gdb "set max-completions 1\n"
+
+mi_gdb_test "2-complete br" \
+            ".*2\\^done,completion=\"br\[A-Za-z0-9-\]+\",matches=\\\[\"br\[A-Za-z0-9-\]+\"\\\],max_completions_reached=\"1\"" \
+            "-complete br (max-completions 1)"
+
+# Disable completions and check an error is returned
+send_gdb "set max-completions 0\n"
+
+mi_gdb_test "3-complete br" \
+            ".*3\\^error,msg=\".*" \
+            "-complete br (max-completions 0)"
-- 
2.20.1