[FFmpeg-devel] [PATCH v3] avutil/avstring: support input path is a null pointer or empty string

[Limin Wang]

ping, please help to push the patchset.

On Fri, Sep 20, 2019 at 10:53:38AM +0800, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Linux and OSX systems support basename and dirname via <libgen.h>, I plan to
> make the wrapper interface conform to the standard interface first.
> If it is feasible, I will continue to modify it to call the system interface
> if there is already a system call interface.
> 
> You can get more descrioption about the system interface by below command:
>  "man 3 basename"
> 
> Reviewed-by: Marton Balint <cus at passwd.hu>
> Reviewed-by: Tomas Härdin <tjoppen at acc.umu.se>
> Reviewed-by: Liu Steven <lq at chinaffmpeg.org>
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>  libavutil/avstring.c | 12 ++++++++----
>  libavutil/avstring.h | 13 +++++++++----
>  2 files changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/libavutil/avstring.c b/libavutil/avstring.c
> index 4c068f5..76a13ba 100644
> --- a/libavutil/avstring.c
> +++ b/libavutil/avstring.c
> @@ -257,8 +257,12 @@ char *av_strireplace(const char *str, const char *from, const char *to)
>  
>  const char *av_basename(const char *path)
>  {
> -    char *p = strrchr(path, '/');
> +    char *p;
>  
> +    if (!path || *path == '\0')
> +        return ".";
> +
> +    p = strrchr(path, '/');
>  #if HAVE_DOS_PATHS
>      char *q = strrchr(path, '\\');
>      char *d = strchr(path, ':');
> @@ -274,11 +278,11 @@ const char *av_basename(const char *path)
>  
>  const char *av_dirname(char *path)
>  {
> -    char *p = strrchr(path, '/');
> +    char *p = path ? strrchr(path, '/') : NULL;
>  
>  #if HAVE_DOS_PATHS
> -    char *q = strrchr(path, '\\');
> -    char *d = strchr(path, ':');
> +    char *q = path ? strrchr(path, '\\') : NULL;
> +    char *d = path ? strchr(path, ':')  : NULL;
>  
>      d = d ? d + 1 : d;
>  
> diff --git a/libavutil/avstring.h b/libavutil/avstring.h
> index 37dd4e2..274335c 100644
> --- a/libavutil/avstring.h
> +++ b/libavutil/avstring.h
> @@ -274,16 +274,21 @@ char *av_strireplace(const char *str, const char *from, const char *to);
>  
>  /**
>   * Thread safe basename.
> - * @param path the path, on DOS both \ and / are considered separators.
> + * @param path the string to parse, on DOS both \ and / are considered separators.
>   * @return pointer to the basename substring.
> + * If path does not contain a slash, the function returns a copy of path.
> + * If path is a NULL pointer or points to an empty string, a pointer
> + * to a string "." is returned.
>   */
>  const char *av_basename(const char *path);
>  
>  /**
>   * Thread safe dirname.
> - * @param path the path, on DOS both \ and / are considered separators.
> - * @return the path with the separator replaced by the string terminator or ".".
> - * @note the function may change the input string.
> + * @param path the string to parse, on DOS both \ and / are considered separators.
> + * @return A pointer to a string that's the parent directory of path.
> + * If path is a NULL pointer or points to an empty string, a pointer
> + * to a string "." is returned.
> + * @note the function may modify the contents of the path, so copies should be passed.
>   */
>  const char *av_dirname(char *path);
>  
> -- 
> 2.9.5
>