player: normalize paths for resuming playback

Paths like foo.mkv, ./foo.mkv .//foo.mkv, ../"$(basename
"$PWD")"/foo.mkv, and C:\foo.mkv and C:/foo.mkv on Windows, use
different config files for resuming playback, so if you quit-watch-later
and later play the same file with a different path, mpv does not resume
playback. This commit normalizes the paths on Unix to fix this.

1 files changed, 52 insertions, 1 deletions

diff --git a/misc/path_utils.c b/misc/path_utils.c
index 14b4a97031..7fbd1084b8 100644
--- a/misc/path_utils.c
+++ b/misc/path_utils.c
@@ -151,10 +151,61 @@ char *mp_getcwd(void *talloc_ctx)
 
 char *mp_normalize_path(void *talloc_ctx, const char *path)
 {
+    if (!path)
+        return NULL;
+
     if (mp_is_url(bstr0(path)))
         return talloc_strdup(talloc_ctx, path);
 
-    return mp_path_join(talloc_ctx, mp_getcwd(talloc_ctx), path);
+    if (!mp_path_is_absolute(bstr0(path))) {
+        char *cwd = mp_getcwd(talloc_ctx);
+        if (!cwd)
+            return NULL;
+        path = mp_path_join(talloc_ctx, cwd, path);
+    }
+
+#if HAVE_DOS_PATHS
+    return talloc_strdup(talloc_ctx, path);
+#else
+    char *result = talloc_strdup(talloc_ctx, "");
+    const char *next;
+    const char *end = path + strlen(path);
+
+    for (const char *ptr = path; ptr < end; ptr = next + 1) {
+        next = memchr(ptr, '/', end - ptr);
+        if (next == NULL)
+            next = end;
+
+        switch (next - ptr) {
+            case 0:
+                continue;
+            case 1:
+                if (ptr[0] == '.')
+                    continue;
+                break;
+            case 2:
+                // Normalizing symlink/.. results in a wrong path: if the
+                // current working directory is /tmp/foo, and it is a symlink to
+                // /usr/bin, mpv ../file.mkv opens /usr/file.mkv, so we can't
+                // normalize the path to /tmp/file.mkv. Resolve symlinks to fix
+                // this. Otherwise we don't use realpath so users can use
+                // symlinks e.g. to hide how media files are distributed over
+                // real storage and move them while still resuming playback as
+                // long as the symlinked path doesn't change.
+                if (ptr[0] == '.' && ptr[1] == '.') {
+                    char *tmp_result = realpath(path, NULL);
+                    result = talloc_strdup(talloc_ctx, tmp_result);
+                    free(tmp_result);
+                    return result;
+                }
+        }
+
+        result = talloc_strdup_append_buffer(result, "/");
+        result = talloc_strndup_append_buffer(result, ptr, next - ptr);
+    }
+
+    return result;
+#endif
 }
 
 bool mp_path_exists(const char *path)