1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "chrome/utility/media_galleries/iapps_xml_utils.h"
6
7 #include "base/logging.h"
8 #include "base/stl_util.h"
9 #include "base/strings/string_number_conversions.h"
10 #include "third_party/libxml/chromium/libxml_utils.h"
11
12 namespace iapps {
13
SkipToNextElement(XmlReader * reader)14 bool SkipToNextElement(XmlReader* reader) {
15 if (!reader->SkipToElement()) {
16 // SkipToElement returns false if the current node is an end element,
17 // try to advance to the next element and then try again.
18 if (!reader->Read() || !reader->SkipToElement())
19 return false;
20 }
21 return true;
22 }
23
SeekToNodeAtCurrentDepth(XmlReader * reader,const std::string & name)24 bool SeekToNodeAtCurrentDepth(XmlReader* reader, const std::string& name) {
25 int depth = reader->Depth();
26 do {
27 if (!SkipToNextElement(reader) || reader->Depth() < depth)
28 return false;
29 DCHECK_EQ(depth, reader->Depth());
30 if (reader->NodeName() == name)
31 return true;
32 } while (reader->Next());
33
34 return false;
35 }
36
SeekInDict(XmlReader * reader,const std::string & key)37 bool SeekInDict(XmlReader* reader, const std::string& key) {
38 DCHECK_EQ("dict", reader->NodeName());
39
40 int dict_content_depth = reader->Depth() + 1;
41 // Advance past the dict node and into the body of the dictionary.
42 if (!reader->Read())
43 return false;
44
45 while (reader->Depth() >= dict_content_depth) {
46 if (!SeekToNodeAtCurrentDepth(reader, "key"))
47 return false;
48 std::string found_key;
49 if (!reader->ReadElementContent(&found_key))
50 return false;
51 DCHECK_EQ(dict_content_depth, reader->Depth());
52 if (found_key == key)
53 return true;
54 }
55 return false;
56 }
57
58 // Seek to the start of a tag and read the value into |result| if the node's
59 // name is |node_name|.
ReadSimpleValue(XmlReader * reader,const std::string & node_name,std::string * result)60 bool ReadSimpleValue(XmlReader* reader, const std::string& node_name,
61 std::string* result) {
62 if (!iapps::SkipToNextElement(reader))
63 return false;
64 if (reader->NodeName() != node_name)
65 return false;
66 return reader->ReadElementContent(result);
67 }
68
ReadString(XmlReader * reader,std::string * result)69 bool ReadString(XmlReader* reader, std::string* result) {
70 return ReadSimpleValue(reader, "string", result);
71 }
72
ReadInteger(XmlReader * reader,uint64 * result)73 bool ReadInteger(XmlReader* reader, uint64* result) {
74 std::string value;
75 if (!ReadSimpleValue(reader, "integer", &value))
76 return false;
77 return base::StringToUint64(value, result);
78 }
79
ReadFileAsString(base::File file)80 std::string ReadFileAsString(base::File file) {
81 std::string result;
82 if (!file.IsValid())
83 return result;
84
85 // A "reasonable" artificial limit.
86 // TODO(vandebo): Add a UMA to figure out what common values are.
87 const int64 kMaxLibraryFileSize = 150 * 1024 * 1024;
88 base::File::Info file_info;
89 if (!file.GetInfo(&file_info) || file_info.size > kMaxLibraryFileSize)
90 return result;
91
92 result.resize(file_info.size);
93 int bytes_read = file.Read(0, string_as_array(&result), file_info.size);
94 if (bytes_read != file_info.size)
95 result.clear();
96
97 return result;
98 }
99
XmlDictReader(XmlReader * reader)100 XmlDictReader::XmlDictReader(XmlReader* reader) : reader_(reader) {}
101
~XmlDictReader()102 XmlDictReader::~XmlDictReader() {}
103
Read()104 bool XmlDictReader::Read() {
105 if (reader_->NodeName() != "dict")
106 return false;
107
108 int dict_content_depth = reader_->Depth() + 1;
109 // Advance past the dict node and into the body of the dictionary.
110 if (!reader_->Read())
111 return false;
112
113 while (reader_->Depth() >= dict_content_depth && ShouldLoop()) {
114 if (!iapps::SeekToNodeAtCurrentDepth(reader_, "key"))
115 break;
116 std::string found_key;
117 if (!reader_->ReadElementContent(&found_key))
118 break;
119 DCHECK_EQ(dict_content_depth, reader_->Depth());
120
121 if (!HandleKey(found_key))
122 break;
123 }
124 // Seek to the end of the dictionary. Bail on end or error.
125 while (reader_->Depth() >= dict_content_depth && reader_->Next()) {
126 }
127 return FinishedOk();
128 }
129
ShouldLoop()130 bool XmlDictReader::ShouldLoop() {
131 return true;
132 }
133
HandleKey(const std::string & key)134 bool XmlDictReader::HandleKey(const std::string& key) {
135 if (Found(key))
136 return AllowRepeats();
137 if (HandleKeyImpl(key)) {
138 found_.insert(key);
139 return true;
140 }
141 return false;
142 }
143
AllowRepeats()144 bool XmlDictReader::AllowRepeats() {
145 return false;
146 }
147
FinishedOk()148 bool XmlDictReader::FinishedOk() {
149 return true;
150 }
151
SkipToNext()152 bool XmlDictReader::SkipToNext() {
153 return SkipToNextElement(reader_) && reader_->Next();
154 }
155
Found(const std::string & key) const156 bool XmlDictReader::Found(const std::string& key) const {
157 return ContainsKey(found_, key);
158 }
159
160 } // namespace iapps
161