1 files changed, 83 insertions, 9 deletions

diff --git a/src/song.c b/src/Song.cxx
index f5cc7c35a..eb4c2e53e 100644
--- a/src/song.c
+++ b/src/Song.cxx
@@ -19,26 +19,31 @@
 
 #include "config.h"
 #include "song.h"
-#include "uri.h"
 #include "directory.h"
+
+extern "C" {
 #include "tag.h"
+}
 
 #include <glib.h>
 
 #include <assert.h>
 
+struct directory detached_root;
+
 static struct song *
 song_alloc(const char *uri, struct directory *parent)
 {
 	size_t uri_length;
-	struct song *song;
 
 	assert(uri);
 	uri_length = strlen(uri);
 	assert(uri_length);
-	song = g_malloc(sizeof(*song) - sizeof(song->uri) + uri_length + 1);
 
-	song->tag = NULL;
+	struct song *song = (struct song *)
+		g_malloc(sizeof(*song) - sizeof(song->uri) + uri_length + 1);
+
+	song->tag = nullptr;
 	memcpy(song->uri, uri, uri_length + 1);
 	song->parent = parent;
 	song->mtime = 0;
@@ -50,13 +55,13 @@ song_alloc(const char *uri, struct directory *parent)
 struct song *
 song_remote_new(const char *uri)
 {
-	return song_alloc(uri, NULL);
+	return song_alloc(uri, nullptr);
 }
 
 struct song *
 song_file_new(const char *path, struct directory *parent)
 {
-	assert((parent == NULL) == (*path == '/'));
+	assert((parent == nullptr) == (*path == '/'));
 
 	return song_alloc(path, parent);
 }
@@ -73,6 +78,35 @@ song_replace_uri(struct song *old_song, const char *uri)
 	return new_song;
 }
 
+struct song *
+song_detached_new(const char *uri)
+{
+	assert(uri != nullptr);
+
+	return song_alloc(uri, &detached_root);
+}
+
+struct song *
+song_dup_detached(const struct song *src)
+{
+	assert(src != nullptr);
+
+	struct song *song;
+	if (song_in_database(src)) {
+		char *uri = song_get_uri(src);
+		song = song_detached_new(uri);
+		g_free(uri);
+	} else
+		song = song_alloc(src->uri, nullptr);
+
+	song->tag = tag_dup(src->tag);
+	song->mtime = src->mtime;
+	song->start_ms = src->start_ms;
+	song->end_ms = src->end_ms;
+
+	return song;
+}
+
 void
 song_free(struct song *song)
 {
@@ -81,17 +115,57 @@ song_free(struct song *song)
 	g_free(song);
 }
 
+gcc_pure
+static inline bool
+directory_equals(const struct directory &a, const struct directory &b)
+{
+	return strcmp(a.path, b.path) == 0;
+}
+
+gcc_pure
+static inline bool
+directory_is_same(const struct directory *a, const struct directory *b)
+{
+	return a == b ||
+		(a != nullptr && b != nullptr &&
+		 directory_equals(*a, *b));
+
+}
+
+bool
+song_equals(const struct song *a, const struct song *b)
+{
+	assert(a != nullptr);
+	assert(b != nullptr);
+
+	if (a->parent != nullptr && b->parent != nullptr &&
+	    !directory_equals(*a->parent, *b->parent) &&
+	    (a->parent == &detached_root || b->parent == &detached_root)) {
+		/* must compare the full URI if one of the objects is
+		   "detached" */
+		char *au = song_get_uri(a);
+		char *bu = song_get_uri(b);
+		const bool result = strcmp(au, bu) == 0;
+		g_free(bu);
+		g_free(au);
+		return result;
+	}
+
+	return directory_is_same(a->parent, b->parent) &&
+		strcmp(a->uri, b->uri) == 0;
+}
+
 char *
 song_get_uri(const struct song *song)
 {
-	assert(song != NULL);
+	assert(song != nullptr);
 	assert(*song->uri);
 
 	if (!song_in_database(song) || directory_is_root(song->parent))
 		return g_strdup(song->uri);
 	else
 		return g_strconcat(directory_get_path(song->parent),
-				   "/", song->uri, NULL);
+				   "/", song->uri, nullptr);
 }
 
 double
@@ -100,7 +174,7 @@ song_get_duration(const struct song *song)
 	if (song->end_ms > 0)
 		return (song->end_ms - song->start_ms) / 1000.0;
 
-	if (song->tag == NULL)
+	if (song->tag == nullptr)
 		return 0;
 
 	return song->tag->time - song->start_ms / 1000.0;