From 760277e096cd35629166367352c108d6ab3b59c2 Mon Sep 17 00:00:00 2001
From: "James D. Smith" <smithjd15@gmail.com>
Date: Sat, 18 Sep 2021 21:09:24 -0600
Subject: [PATCH] Dir cache: Fix resume of relative path playlists.

Slightly modified from original patch by Fabrice Bellard.

Change-Id: I9ae04fa460f0f1b9c616e6f99505d4c5d4358f68
---
 apps/playlist.c             |  9 ++++---
 firmware/common/pathfuncs.c | 51 +++++++++++++++++++++++++++++++++++++
 firmware/export/pathfuncs.h |  1 +
 3 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/apps/playlist.c b/apps/playlist.c
index 49c52a9b7e..0d02be3d48 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -1762,9 +1762,8 @@ static ssize_t format_track_path(char *dest, char *src, int buf_length,
      * to "/<0>/bar" (aka "/bar" at this time). *fingers crossed*
      *
      * If any stripped drive spec was absolute, prepend the playlist
-     * directory's volume spec, or root if none. Relative paths remain
-     * relative and the playlist's directory fully qualifies them. Absolute
-     * UNIX-style paths remain unaltered.
+     * directory's volume spec, or root if none. Absolute UNIX-style paths
+     * remain unaltered.
      */
     if (path_strip_drive(src, (const char **)&src, true) >= 0 &&
         src[-1] == PATH_SEPCH)
@@ -1782,7 +1781,9 @@ static ssize_t format_track_path(char *dest, char *src, int buf_length,
     if (len >= (size_t)buf_length)
         return -1; /* buffer too small */
 
-    return len;
+    path_remove_dot_segments (dest, dest);
+
+    return strlen (dest);
 }
 
 /*
diff --git a/firmware/common/pathfuncs.c b/firmware/common/pathfuncs.c
index 1c48a54972..2b4e6a8eb0 100644
--- a/firmware/common/pathfuncs.c
+++ b/firmware/common/pathfuncs.c
@@ -340,6 +340,57 @@ void path_correct_separators(char *dstpath, const char *path)
         strcpy(dstp, p);
 }
 
+/* Remove dot segments from the path
+ *
+ * 'path' and 'dstpath' may either be the same buffer or non-overlapping
+ */
+void path_remove_dot_segments (char *dstpath, const char *path)
+{
+    char *dstp = dstpath;
+    char *odstp = dstpath;
+    const char *p = path;
+
+    while (*p)
+    {
+        if (p[0] == '.' && p[1] == PATH_SEPCH)
+            p += 2;
+        else if (p[0] == '.' && p[1] == '.' && p[2] == PATH_SEPCH)
+            p += 3;
+        else if (p[0] == PATH_SEPCH && p[1] == '.' && p[2] == PATH_SEPCH)
+            p += 2;
+        else if (p[0] == PATH_SEPCH && p[1] == '.' && !p[2])
+        {
+            *dstp++ = PATH_SEPCH;
+            break;
+        }
+        else if (p[0] == PATH_SEPCH && p[1] == '.' &&
+            p[2] == '.' && p[3] == PATH_SEPCH)
+        {
+            dstp = odstp;
+            p += 3;
+        }
+        else if (p[0] == PATH_SEPCH && p[1] == '.' && p[2] == '.' && !p[3])
+        {
+            dstp = odstp;
+            *dstp++ = PATH_SEPCH;
+            break;
+        }
+        else if (p[0] == '.' && !p[1])
+            break;
+        else if (p[0] == '.' && p[1] == '.' && !p[2])
+            break;
+        else
+        {
+            odstp = dstp;
+            if (p[0] == PATH_SEPCH)
+                *dstp++ = *p++;
+            while (p[0] && p[0] != PATH_SEPCH)
+                *dstp++ = *p++;
+        }
+    }
+    *dstp = 0;
+}
+
 /* Appends one path to another, adding separators between components if needed.
  * Return value and behavior is otherwise as strlcpy so that truncation may be
  * detected.
diff --git a/firmware/export/pathfuncs.h b/firmware/export/pathfuncs.h
index 92539c54c1..350dd4e548 100644
--- a/firmware/export/pathfuncs.h
+++ b/firmware/export/pathfuncs.h
@@ -82,6 +82,7 @@ size_t path_basename(const char *name, const char **nameptr);
 size_t path_dirname(const char *name, const char **nameptr);
 size_t path_strip_trailing_separators(const char *name, const char **nameptr);
 void path_correct_separators(char *dstpath, const char *path);
+void path_remove_dot_segments(char *dstpath, const char *path);
 
 /* constants useable in basepath and component */
 #define PA_SEP_HARD NULL /* separate even if base is empty */