Generally, this seems to be too complicated with too much of copying.
On Mon, Jul 27, 2020 at 3:08 PM Steven Liu <l...@chinaffmpeg.org> wrote:
> use two buffer for storage the path and node of URI
> remove the last node of the path if the next node is ..
> change the static strings to dynamic alloc space by size argument.
>
> Signed-off-by: Steven Liu <l...@chinaffmpeg.org>
> ---
> libavformat/url.c | 83 ++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 64 insertions(+), 19 deletions(-)
>
> diff --git a/libavformat/url.c b/libavformat/url.c
> index 20463a6674..4fb703de78 100644
> --- a/libavformat/url.c
> +++ b/libavformat/url.c
> @@ -82,41 +82,78 @@ static void trim_double_dot_url(char *buf, const char
> *rel, int size)
> {
> const char *p = rel;
> const char *root = rel;
> - char tmp_path[MAX_URL_SIZE] = {0, };
> + char *tmp_path = NULL;
> + char *second_buf = NULL;
> + char *first_buf = NULL;
> char *sep;
> char *node;
>
> + tmp_path = av_mallocz(size);
> + if (!tmp_path)
> + return;
> +
> + second_buf = av_mallocz(size);
> + if (!second_buf)
> + goto fail;
> +
> + first_buf = av_mallocz(size);
> + if (!first_buf)
> + goto fail;
>
Why 3 buffers? 1 would be enough.
+
> /* Get the path root of the url which start by "://" */
> if (p && (sep = strstr(p, "://"))) {
> sep += 3;
> root = strchr(sep, '/');
> if (!root)
> - return;
> + goto fail;
> }
> + av_strlcat(tmp_path, p, root - p + 1);
>
> /* set new current position if the root node is changed */
> p = root;
> - while (p && (node = strstr(p, ".."))) {
> - av_strlcat(tmp_path, p, node - p + strlen(tmp_path));
> - p = node + 3;
> - sep = strrchr(tmp_path, '/');
> + if (*p == '/')
> + p++;
> + while (p && (node = strchr(p, '/'))) {
> + av_strlcpy(second_buf, p, node - p + 1);
> + p = node + 1;
> + if (!strcmp(second_buf, "..")) {
>
If you used if(node - p == 2 && !strncmp(node, "..", 2)) you would not have
to copy to the second buffer.
+ if (strlen(first_buf) <= 0)
> + continue;
> + sep = strrchr(first_buf, '/');
> + if (sep)
> + sep[0] = '\0';
> + else
> + memset(first_buf, 0, size);
> +
> + memset(second_buf, 0, size);
> + } else {
> + av_strlcat(first_buf, "/", size);
> + av_strlcat(first_buf, second_buf, size);
> + }
> + }
> + if (!strcmp(p, "..")) {
> + sep = strrchr(first_buf, '/');
> if (sep)
> sep[0] = '\0';
> else
> - tmp_path[0] = '\0';
> + memset(first_buf, 0, size);
> + } else {
> + av_strlcat(first_buf, "/", size);
> + av_strlcat(first_buf, p, size);
> }
>
> - if (!av_stristart(p, "/", NULL) && root != rel)
> - av_strlcat(tmp_path, "/", size);
> -
> - av_strlcat(tmp_path, p, size);
> - /* start set buf after temp path process. */
> - av_strlcpy(buf, rel, root - rel + 1);
> -
> - if (!av_stristart(tmp_path, "/", NULL) && root != rel)
> - av_strlcat(buf, "/", size);
> + if (p > root) {
> + av_strlcat(tmp_path, first_buf, size);
> + } else {
> + av_strlcat(tmp_path, p, size);
> + }
>
> av_strlcat(buf, tmp_path, size);
> +
> +fail:
> + av_free(second_buf);
> + av_free(first_buf);
> + av_free(tmp_path);
> }
>
> void ff_make_absolute_url(char *buf, int size, const char *base,
> @@ -124,9 +161,11 @@ void ff_make_absolute_url(char *buf, int size, const
> char *base,
> {
> char *sep, *path_query;
> char *root, *p;
> - char tmp_path[MAX_URL_SIZE];
> + char *tmp_path = av_mallocz(size);
> +
> + if (!tmp_path)
> + return;
>
> - memset(tmp_path, 0, sizeof(tmp_path));
> /* Absolute path, relative to the current server */
> if (base && strstr(base, "://") && rel[0] == '/') {
> if (base != buf)
> @@ -148,12 +187,14 @@ void ff_make_absolute_url(char *buf, int size, const
> char *base,
> trim_double_dot_url(tmp_path, buf, size);
> memset(buf, 0, size);
> av_strlcpy(buf, tmp_path, size);
> + av_free(tmp_path);
> return;
> }
> /* If rel actually is an absolute url, just copy it */
> if (!base || strstr(rel, "://") || rel[0] == '/') {
> memset(buf, 0, size);
> trim_double_dot_url(buf, rel, size);
> + av_free(tmp_path);
> return;
> }
> if (base != buf)
> @@ -170,6 +211,7 @@ void ff_make_absolute_url(char *buf, int size, const
> char *base,
> trim_double_dot_url(tmp_path, buf, size);
> memset(buf, 0, size);
> av_strlcpy(buf, tmp_path, size);
> + av_free(tmp_path);
> return;
> }
>
> @@ -180,8 +222,10 @@ void ff_make_absolute_url(char *buf, int size, const
> char *base,
> if (sep) {
> sep += 3;
> root = strchr(sep, '/');
> - if (!root)
> + if (!root) {
> + av_free(tmp_path);
> return;
> + }
> }
> }
>
> @@ -218,6 +262,7 @@ void ff_make_absolute_url(char *buf, int size, const
> char *base,
> trim_double_dot_url(tmp_path, buf, size);
> memset(buf, 0, size);
> av_strlcpy(buf, tmp_path, size);
> + av_free(tmp_path);
> }
>
> AVIODirEntry *ff_alloc_dir_entry(void)
> --
> 2.25.0
>
>
>
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--
Josef Zlomek
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