Re: [PATCH] Use strtok_r instead of strsep in rust_get_disr_info

[Manish Goregaokar <manish@mozilla.com>]

Actually, it occurs to me that token could still be null after the
loop, and we use the value of token to get the name.

New patch:

--------------


strsep doesn't exist on Windows.

2016-06-29  Manish Goregaokar  <manish@mozilla.com>

gdb/ChangeLog:
    * rust-lang.c (rust_get_disr_info): Use strtok_r instead of strsep.
---
 gdb/rust-lang.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index 23ddd5a..c01687a 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -121,7 +121,7 @@ rust_get_disr_info (struct type *type, const
gdb_byte *valaddr,
   if (strncmp (TYPE_FIELD_NAME (type, 0), RUST_ENUM_PREFIX,
            strlen (RUST_ENUM_PREFIX)) == 0)
     {
-      char *name, *tail, *token;
+      char *tail, *token, *name, *saveptr;
       unsigned long fieldno;
       struct type *member_type;
       LONGEST value;
@@ -145,7 +145,9 @@ rust_get_disr_info (struct type *type, const
gdb_byte *valaddr,
          traversed in order to find the field (which may be several
fields deep)
          and the variantname is the name of the variant of the case when the
          field is zero.  */
-      while ((token = strsep (&tail, "$")) != NULL)
+      for (token = strtok_r (tail, "$", &saveptr);
+           token != NULL;
+           token = strtok_r (NULL, "$", &saveptr))
         {
       if (sscanf (token, "%lu", &fieldno) != 1)
         {
@@ -161,7 +163,7 @@ rust_get_disr_info (struct type *type, const
gdb_byte *valaddr,
           member_type = TYPE_FIELD_TYPE (member_type, fieldno);
         }

-      if (token >= name + strlen (TYPE_FIELD_NAME (type, 0)))
+      if (token == NULL)
     error (_("Invalid form for %s"), RUST_ENUM_PREFIX);
       value = unpack_long (member_type, valaddr + embedded_offset);

-- 
2.8.3

-Manish


On Wed, Jun 29, 2016 at 4:01 PM, Manish Goregaokar <manish@mozilla.com> wrote:
> Fixed.
>
> From 6b577bb78279a453c77b08c5a1090d8dec1eeee7 Mon Sep 17 00:00:00 2001
> From: Manish Goregaokar <manish@mozilla.com>
> Date: Wed, 29 Jun 2016 15:42:28 +0530
> Subject: [PATCH] Use strtok_r instead of strsep in rust_get_disr_info
>
> strsep doesn't exist on Windows.
>
> 2016-06-29  Manish Goregaokar  <manish@mozilla.com>
>
> gdb/ChangeLog:
>     * rust-lang.c (rust_get_disr_info): Use strtok_r instead of strsep.
> ---
>  gdb/rust-lang.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
> index 23ddd5a..5910d4b 100644
> --- a/gdb/rust-lang.c
> +++ b/gdb/rust-lang.c
> @@ -121,7 +121,7 @@ rust_get_disr_info (struct type *type, const
> gdb_byte *valaddr,
>    if (strncmp (TYPE_FIELD_NAME (type, 0), RUST_ENUM_PREFIX,
>             strlen (RUST_ENUM_PREFIX)) == 0)
>      {
> -      char *name, *tail, *token;
> +      char *tail, *token, *name, *saveptr;
>        unsigned long fieldno;
>        struct type *member_type;
>        LONGEST value;
> @@ -145,7 +145,9 @@ rust_get_disr_info (struct type *type, const
> gdb_byte *valaddr,
>           traversed in order to find the field (which may be several
> fields deep)
>           and the variantname is the name of the variant of the case when the
>           field is zero.  */
> -      while ((token = strsep (&tail, "$")) != NULL)
> +      for (token = strtok_r (tail, "$", &saveptr);
> +           token != NULL;
> +           token = strtok_r (NULL, "$", &saveptr))
>          {
>        if (sscanf (token, "%lu", &fieldno) != 1)
>          {
> @@ -161,8 +163,6 @@ rust_get_disr_info (struct type *type, const
> gdb_byte *valaddr,
>            member_type = TYPE_FIELD_TYPE (member_type, fieldno);
>          }
>
> -      if (token >= name + strlen (TYPE_FIELD_NAME (type, 0)))
> -    error (_("Invalid form for %s"), RUST_ENUM_PREFIX);
>        value = unpack_long (member_type, valaddr + embedded_offset);
>
>        if (value == 0)
> --
> 2.8.3
>
> -Manish
>
>
> On Wed, Jun 29, 2016 at 3:56 PM, Pedro Alves <palves@redhat.com> wrote:
>> (stepping in since this fixes a build breakage.)
>>
>> On 06/29/2016 11:13 AM, Manish Goregaokar wrote:
>>> strsep doesn't exist on windows
>>
>> "Windows", uppercase.
>>
>>>
>>> 2016-06-29  Manish Goregaokar  <manish@mozilla.com>
>>>
>>> gdb/ChangeLog:
>>>     * rust-lang.c (rust_get_disr_info): Use strtok_r instead of strsep
>>
>> Period at end of sentences.  Likewise on the commit log,
>> while at it.
>>
>>> ---
>>>  gdb/rust-lang.c | 10 +++++-----
>>>  1 file changed, 5 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
>>> index 23ddd5a..961fdca 100644
>>> --- a/gdb/rust-lang.c
>>> +++ b/gdb/rust-lang.c
>>> @@ -121,7 +121,7 @@ rust_get_disr_info (struct type *type, const
>>> gdb_byte *valaddr,
>>>    if (strncmp (TYPE_FIELD_NAME (type, 0), RUST_ENUM_PREFIX,
>>>             strlen (RUST_ENUM_PREFIX)) == 0)
>>>      {
>>> -      char *name, *tail, *token;
>>> +      char *tail, *token, *name, *last = NULL;
>>
>> (I don't think you need to initialize this.  If you get
>> a warning about it, it's likely revealing a bug.)
>>
>>>        unsigned long fieldno;
>>>        struct type *member_type;
>>>        LONGEST value;
>>> @@ -138,6 +138,8 @@ rust_get_disr_info (struct type *type, const
>>> gdb_byte *valaddr,
>>>        cleanup = make_cleanup (xfree, name);
>>>        tail = name + strlen (RUST_ENUM_PREFIX);
>>>
>>> +      token = strtok_r (tail, "$", &last);
>>> +
>>>        /* The location of the value that doubles as a discriminant is
>>>           stored in the name of the field, as
>>>           RUST$ENCODED$ENUM$<fieldno>$<fieldno>$...$<variantname>
>>> @@ -145,7 +147,7 @@ rust_get_disr_info (struct type *type, const
>>> gdb_byte *valaddr,
>>>           traversed in order to find the field (which may be several
>>> fields deep)
>>>           and the variantname is the name of the variant of the case when the
>>>           field is zero.  */
>>> -      while ((token = strsep (&tail, "$")) != NULL)
>>> +      do
>>>          {
>>>        if (sscanf (token, "%lu", &fieldno) != 1)
>>
>> We'll now reach here even if token is NULL the first time.
>>
>>>          {
>>> @@ -159,10 +161,8 @@ rust_get_disr_info (struct type *type, const
>>> gdb_byte *valaddr,
>>>
>>>            embedded_offset += TYPE_FIELD_BITPOS (member_type, fieldno) / 8;
>>>            member_type = TYPE_FIELD_TYPE (member_type, fieldno);
>>> -        }
>>> +        } while ((token = strtok_r (NULL, "$", &last)) != NULL);
>>
>> IMO, this calls for a "for" loop instead of a do/while.  Like:
>>
>>  -      while ((token = strsep (&tail, "$")) != NULL)
>>  +      for (token = strtok_r (tail, "$", &saveptr);
>>  +           token != NULL;
>>  +           token = strtok_r (NULL, "$", &saveptr))
>>          {
>>
>> Thanks,
>> Pedro Alves
>>