db/Helpers: move code to tag/Set.cxx

2 files changed, 130 insertions, 1 deletions

diff --git a/src/tag/Set.cxx b/src/tag/Set.cxx
new file mode 100644
index 000000000..59f66bf84
--- /dev/null
+++ b/src/tag/Set.cxx
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "Set.hxx"
+#include "TagBuilder.hxx"
+
+#include <assert.h>
+
+/**
+ * Copy all tag items of the specified type.
+ */
+static bool
+CopyTagItem(TagBuilder &dest, TagType dest_type,
+	    const Tag &src, TagType src_type)
+{
+	bool found = false;
+	const unsigned n = src.num_items;
+	for (unsigned i = 0; i < n; ++i) {
+		if (src.items[i]->type == src_type) {
+			dest.AddItem(dest_type, src.items[i]->value);
+			found = true;
+		}
+	}
+
+	return found;
+}
+
+/**
+ * Copy all tag items of the specified type.  Fall back to "Artist" if
+ * there is no "AlbumArtist".
+ */
+static void
+CopyTagItem(TagBuilder &dest, const Tag &src, TagType type)
+{
+	if (!CopyTagItem(dest, type, src, type) &&
+	    type == TAG_ALBUM_ARTIST)
+		CopyTagItem(dest, type, src, TAG_ARTIST);
+}
+
+/**
+ * Copy all tag items of the types in the mask.
+ */
+static void
+CopyTagMask(TagBuilder &dest, const Tag &src, uint32_t mask)
+{
+	for (unsigned i = 0; i < TAG_NUM_OF_ITEM_TYPES; ++i)
+		if ((mask & (1u << i)) != 0)
+			CopyTagItem(dest, src, TagType(i));
+}
+
+void
+TagSet::InsertUnique(const Tag &src, TagType type, const char *value,
+		     uint32_t group_mask)
+{
+	TagBuilder builder;
+	if (value == nullptr)
+		builder.AddEmptyItem(type);
+	else
+		builder.AddItem(type, value);
+	CopyTagMask(builder, src, group_mask);
+#if defined(__clang__) || GCC_CHECK_VERSION(4,8)
+	emplace(builder.Commit());
+#else
+	insert(builder.Commit());
+#endif
+}
+
+bool
+TagSet::CheckUnique(TagType dest_type,
+		    const Tag &tag, TagType src_type,
+		    uint32_t group_mask)
+{
+	bool found = false;
+	for (unsigned i = 0; i < tag.num_items; ++i) {
+		if (tag.items[i]->type == src_type) {
+			InsertUnique(tag, dest_type,
+					tag.items[i]->value,
+					group_mask);
+			found = true;
+		}
+	}
+
+	return found;
+}
+
+void
+TagSet::InsertUnique(const Tag &tag,
+		     TagType type, uint32_t group_mask)
+{
+	static_assert(sizeof(group_mask) * 8 >= TAG_NUM_OF_ITEM_TYPES,
+		      "Mask is too small");
+
+	assert((group_mask & (1u << unsigned(type))) == 0);
+
+	if (!CheckUnique(type, tag, type, group_mask) &&
+	    (type != TAG_ALBUM_ARTIST ||
+	     /* fall back to "Artist" if no "AlbumArtist" was found */
+	     !CheckUnique(type, tag, TAG_ARTIST, group_mask)))
+		InsertUnique(tag, type, nullptr, group_mask);
+}
diff --git a/src/tag/Set.hxx b/src/tag/Set.hxx
index 3b9654807..b5acfcb36 100644
--- a/src/tag/Set.hxx
+++ b/src/tag/Set.hxx
@@ -26,6 +26,7 @@
 #include <set>
 
 #include <string.h>
+#include <stdint.h>
 
 /**
  * Helper class for #TagSet which compares two #Tag objects.
@@ -55,6 +56,18 @@ struct TagLess {
 /**
  * A set of #Tag objects.
  */
-typedef std::set<Tag, TagLess> TagSet;
+class TagSet : public std::set<Tag, TagLess> {
+public:
+	void InsertUnique(const Tag &tag,
+			  TagType type, uint32_t group_mask);
+
+private:
+	void InsertUnique(const Tag &src, TagType type, const char *value,
+			  uint32_t group_mask);
+
+	bool CheckUnique(TagType dest_type,
+			 const Tag &tag, TagType src_type,
+			 uint32_t group_mask);
+};
 
 #endif