[FFmpeg-devel] [PATCH v3 1/2] avformat/url: rework for trim_double_dot_url

[Steven Liu]

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 <lq at 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;
+
     /* 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 (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