[FFmpeg-devel] [PATCH 4/6] lavu/avstring: add av_append_path_component() funcion

[wm4]

On Sat,  5 Jul 2014 18:12:02 +0200
Lukasz Marek <lukasz.m.luki2 at gmail.com> wrote:

> TODO: bump minor, update doc/APIchanges
> 
> Convinient function to build paths.
> 
> Signed-off-by: Lukasz Marek <lukasz.m.luki2 at gmail.com>
> ---
>  libavutil/avstring.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  libavutil/avstring.h | 10 ++++++++++
>  2 files changed, 53 insertions(+)
> 
> diff --git a/libavutil/avstring.c b/libavutil/avstring.c
> index e75cdc6..d7060ab 100644
> --- a/libavutil/avstring.c
> +++ b/libavutil/avstring.c
> @@ -268,6 +268,35 @@ const char *av_dirname(char *path)
>      return path;
>  }
>  
> +char *av_append_path_component(const char *path, const char *component)
> +{
> +    size_t p_len, c_len;
> +    char *fullpath;
> +
> +    if (!path)
> +        return component ? av_strdup(component) : NULL;
> +    if (!component)
> +        return av_strdup(path);
> +
> +    p_len = strlen(path);
> +    c_len = strlen(component);
> +    fullpath = malloc(p_len + c_len + 2);
> +    if (fullpath) {
> +        if (p_len) {
> +            strcpy(fullpath, path);
> +            if (c_len) {
> +                if (fullpath[p_len - 1] != '/' && component[0] != '/')
> +                    fullpath[p_len++] = '/';
> +                else if (fullpath[p_len - 1] == '/' && component[0] == '/')

What about MS Windows paths?

> +                    p_len--;
> +            }
> +        }
> +        strcpy(&fullpath[p_len], component);
> +        fullpath[p_len + c_len] = 0;

Maybe use snprintf() instead of the utterly broken strcpy function?

(Didn't really look at the rest of the logic.)

> +    }
> +    return fullpath;
> +}
> +
>  int av_escape(char **dst, const char *src, const char *special_chars,
>                enum AVEscapeMode mode, int flags)
>  {
> @@ -376,6 +405,7 @@ end:
>  int main(void)
>  {
>      int i;
> +    char *fullpath;
>      static const char * const strings[] = {
>          "''",
>          "",
> @@ -416,6 +446,19 @@ int main(void)
>          av_free(q);
>      }
>  
> +    printf("Testing av_append_path_component()\n");
> +    #define TEST_APPEND_PATH_COMPONENT(path, component, expected) \
> +        fullpath = av_append_path_component((path), (component)); \
> +        printf("%s = %s\n", fullpath, expected); \
> +        av_free(fullpath);
> +    TEST_APPEND_PATH_COMPONENT(NULL, NULL, "(null)")
> +    TEST_APPEND_PATH_COMPONENT("path", NULL, "path");
> +    TEST_APPEND_PATH_COMPONENT(NULL, "comp", "comp");
> +    TEST_APPEND_PATH_COMPONENT("path", "comp", "path/comp");
> +    TEST_APPEND_PATH_COMPONENT("path/", "comp", "path/comp");
> +    TEST_APPEND_PATH_COMPONENT("path", "/comp", "path/comp");
> +    TEST_APPEND_PATH_COMPONENT("path/", "/comp", "path/comp");
> +    TEST_APPEND_PATH_COMPONENT("path/path2/", "/comp/comp2", "path/path2/comp/comp2");
>      return 0;
>  }
>  
> diff --git a/libavutil/avstring.h b/libavutil/avstring.h
> index de2f71d..0a91dbf 100644
> --- a/libavutil/avstring.h
> +++ b/libavutil/avstring.h
> @@ -268,6 +268,16 @@ const char *av_basename(const char *path);
>   */
>  const char *av_dirname(char *path);
>  
> +/**
> + * Append path component to the existing path.
> + * Path separator '/' is placed between when needed.
> + * Resulting string have to be freed with av_free().
> + * @param path      base path
> + * @param component component to be appended
> + * @return new path or NULL on error.
> + */
> +char *av_append_path_component(const char *path, const char *component);

IMO the name is awkward. Maybe av_path_join()?

Did you have a look at Python's os.path.join()? IMO it has pretty good
and well documented semantics, which you could steal.

> +
>  enum AVEscapeMode {
>      AV_ESCAPE_MODE_AUTO,      ///< Use auto-selected escaping mode.
>      AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.