Extract track information from iTunes library xml file.

chrome/browser/media_galleries/fileapi/itunes_xml_utils.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/media_galleries/fileapi/itunes_xml_utils.h"
+#include <string>
+
+#include "base/logging.h"
+#include "third_party/libxml/chromium/libxml_utils.h"
+
+namespace itunes {
+
+bool SkipToNextElement(XmlReader* reader) {
+  if (!reader->SkipToElement()) {
+    // SkipToElement returns false if the current node is an end element,
+    // try to advance to the next element and then try again.
+    if (!reader->Read() || !reader->SkipToElement())
+      return false;
+  }
+  return true;
+}
+
+bool SeekToNodeAtCurrentDepth(XmlReader* reader, const std::string& name) {
+  int depth = reader->Depth();
+  do {
+    if (!SkipToNextElement(reader))
+      return false;
+    DCHECK_EQ(depth, reader->Depth());
+    if (reader->NodeName() == name)
+      return true;
+  } while (reader->Next());
+
+  return false;
+}
+
+bool SeekInDict(XmlReader* reader, const std::string& key) {
+  DCHECK_EQ("dict", reader->NodeName());
+
+  int dict_content_depth = reader->Depth() + 1;
+  // Advance past the dict node and into the body of the dictionary.
+  if (!reader->Read())
+    return false;
+
+  while (reader->Depth() >= dict_content_depth) {
+    if (!SeekToNodeAtCurrentDepth(reader, "key"))
+      return false;
+    std::string found_key;
+    if (!reader->ReadElementContent(&found_key))
+      return false;
+    DCHECK_EQ(dict_content_depth, reader->Depth());
+    if (found_key == key)
+      return true;
+  }
+  return false;
+}
+
+}  // namespace itunes