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1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef AAPT_RESOURCEUTILS_H
18 #define AAPT_RESOURCEUTILS_H
19 
20 #include <functional>
21 #include <memory>
22 
23 #include "androidfw/AssetManager2.h"
24 #include "androidfw/ConfigDescription.h"
25 #include "androidfw/ResourceTypes.h"
26 #include "androidfw/StringPiece.h"
27 
28 #include "NameMangler.h"
29 #include "Resource.h"
30 #include "ResourceValues.h"
31 #include "StringPool.h"
32 
33 namespace aapt {
34 namespace ResourceUtils {
35 
36 /**
37  * Returns true if the string was parsed as a resource name
38  * ([*][package:]type/name), with
39  * `out_resource` set to the parsed resource name and `out_private` set to true
40  * if a '*' prefix was present.
41  */
42 bool ParseResourceName(const android::StringPiece& str, ResourceNameRef* out_resource,
43                        bool* out_private = nullptr);
44 
45 /*
46  * Returns true if the string was parsed as a reference
47  * (@[+][package:]type/name), with
48  * `out_reference` set to the parsed reference.
49  *
50  * If '+' was present in the reference, `out_create` is set to true.
51  * If '*' was present in the reference, `out_private` is set to true.
52  */
53 bool ParseReference(const android::StringPiece& str, ResourceNameRef* out_reference,
54                     bool* out_create = nullptr, bool* out_private = nullptr);
55 
56 /*
57  * Returns true if the string is in the form of a resource reference
58  * (@[+][package:]type/name).
59  */
60 bool IsReference(const android::StringPiece& str);
61 
62 /*
63  * Returns true if the string was parsed as an attribute reference
64  * (?[package:][type/]name),
65  * with `out_reference` set to the parsed reference.
66  */
67 bool ParseAttributeReference(const android::StringPiece& str, ResourceNameRef* out_reference);
68 
69 /**
70  * Returns true if the string is in the form of an attribute
71  * reference(?[package:][type/]name).
72  */
73 bool IsAttributeReference(const android::StringPiece& str);
74 
75 /**
76  * Convert an android::ResTable::resource_name to an aapt::ResourceName struct.
77  */
78 std::optional<ResourceName> ToResourceName(const android::ResTable::resource_name& name);
79 
80 /**
81  * Convert an android::AssetManager2::ResourceName to an aapt::ResourceName struct.
82  */
83 std::optional<ResourceName> ToResourceName(const android::AssetManager2::ResourceName& name_in);
84 
85 /**
86  * Returns a boolean value if the string is equal to TRUE, true, True, FALSE,
87  * false, or False.
88  */
89 std::optional<bool> ParseBool(const android::StringPiece& str);
90 
91 /**
92  * Returns a uint32_t if the string is an integer.
93  */
94 std::optional<uint32_t> ParseInt(const android::StringPiece& str);
95 
96 /**
97  * Returns an ID if it the string represented a valid ID.
98  */
99 std::optional<ResourceId> ParseResourceId(const android::StringPiece& str);
100 
101 /**
102  * Parses an SDK version, which can be an integer, or a letter from A-Z.
103  */
104 std::optional<int> ParseSdkVersion(const android::StringPiece& str);
105 
106 /*
107  * Returns a Reference, or None Maybe instance if the string `str` was parsed as
108  * a
109  * valid reference to a style.
110  * The format for a style parent is slightly more flexible than a normal
111  * reference:
112  *
113  * @[package:]style/<entry> or
114  * ?[package:]style/<entry> or
115  * <package>:[style/]<entry>
116  */
117 std::optional<Reference> ParseStyleParentReference(const android::StringPiece& str,
118                                                    std::string* out_error);
119 
120 /*
121  * Returns a Reference if the string `str` was parsed as a valid XML attribute
122  * name.
123  * The valid format for an XML attribute name is:
124  *
125  * package:entry
126  */
127 std::optional<Reference> ParseXmlAttributeName(const android::StringPiece& str);
128 
129 /*
130  * Returns a Reference object if the string was parsed as a resource or
131  * attribute reference,
132  * ( @[+][package:]type/name | ?[package:]type/name ) setting outCreate to true
133  * if
134  * the '+' was present in the string.
135  */
136 std::unique_ptr<Reference> TryParseReference(const android::StringPiece& str,
137                                              bool* out_create = nullptr);
138 
139 /*
140  * Returns a BinaryPrimitve object representing @null or @empty if the string
141  * was parsed as one.
142  */
143 std::unique_ptr<Item> TryParseNullOrEmpty(const android::StringPiece& str);
144 
145 // Returns a Reference representing @null.
146 // Due to runtime compatibility issues, this is encoded as a reference with ID 0.
147 // The runtime will convert this to TYPE_NULL.
148 std::unique_ptr<Reference> MakeNull();
149 
150 // Returns a BinaryPrimitive representing @empty. This is encoded as a Res_value with
151 // type Res_value::TYPE_NULL and data Res_value::DATA_NULL_EMPTY.
152 std::unique_ptr<BinaryPrimitive> MakeEmpty();
153 
154 /*
155  * Returns a BinaryPrimitve object representing a color if the string was parsed
156  * as one.
157  */
158 std::unique_ptr<BinaryPrimitive> TryParseColor(const android::StringPiece& str);
159 
160 /*
161  * Returns a BinaryPrimitve object representing a boolean if the string was
162  * parsed as one.
163  */
164 std::unique_ptr<BinaryPrimitive> TryParseBool(const android::StringPiece& str);
165 
166 // Returns a boolean BinaryPrimitive.
167 std::unique_ptr<BinaryPrimitive> MakeBool(bool val);
168 
169 /*
170  * Returns a BinaryPrimitve object representing an integer if the string was
171  * parsed as one.
172  */
173 std::unique_ptr<BinaryPrimitive> TryParseInt(const android::StringPiece& str);
174 
175 // Returns an integer BinaryPrimitive.
176 std::unique_ptr<BinaryPrimitive> MakeInt(uint32_t value);
177 
178 /*
179  * Returns a BinaryPrimitve object representing a floating point number
180  * (float, dimension, etc) if the string was parsed as one.
181  */
182 std::unique_ptr<BinaryPrimitive> TryParseFloat(const android::StringPiece& str);
183 
184 /*
185  * Returns a BinaryPrimitve object representing an enum symbol if the string was
186  * parsed as one.
187  */
188 std::unique_ptr<BinaryPrimitive> TryParseEnumSymbol(const Attribute* enum_attr,
189                                                     const android::StringPiece& str);
190 
191 /*
192  * Returns a BinaryPrimitve object representing a flag symbol if the string was
193  * parsed as one.
194  */
195 std::unique_ptr<BinaryPrimitive> TryParseFlagSymbol(const Attribute* enum_attr,
196                                                     const android::StringPiece& str);
197 /*
198  * Try to convert a string to an Item for the given attribute. The attribute
199  * will
200  * restrict what values the string can be converted to.
201  * The callback function on_create_reference is called when the parsed item is a
202  * reference to an ID that must be created (@+id/foo).
203  */
204 std::unique_ptr<Item> TryParseItemForAttribute(
205     const android::StringPiece& value, const Attribute* attr,
206     const std::function<bool(const ResourceName&)>& on_create_reference = {});
207 
208 std::unique_ptr<Item> TryParseItemForAttribute(
209     const android::StringPiece& value, uint32_t type_mask,
210     const std::function<bool(const ResourceName&)>& on_create_reference = {});
211 
212 uint32_t AndroidTypeToAttributeTypeMask(uint16_t type);
213 
214 /**
215  * Returns a string path suitable for use within an APK. The path will look
216  * like:
217  *
218  * res/type[-config]/<name>.<ext>
219  *
220  * Then name may be mangled if a NameMangler is supplied (can be nullptr) and
221  * the package
222  * requires mangling.
223  */
224 std::string BuildResourceFileName(const ResourceFile& res_file,
225                                   const NameMangler* mangler = nullptr);
226 
227 // Parses the binary form of a resource value. `type` is used as a hint to know when a value is
228 // an ID versus a False boolean value, etc. `config` is for sorting strings in the string pool.
229 std::unique_ptr<Item> ParseBinaryResValue(const ResourceType& type,
230                                           const android::ConfigDescription& config,
231                                           const android::ResStringPool& src_pool,
232                                           const android::Res_value& res_value,
233                                           StringPool* dst_pool);
234 
235 // A string flattened from an XML hierarchy, which maintains tags and untranslatable sections
236 // in parallel data structures.
237 struct FlattenedXmlString {
238   std::string text;
239   std::vector<UntranslatableSection> untranslatable_sections;
240   std::vector<Span> spans;
241 };
242 
243 // Flattens an XML hierarchy into a FlattenedXmlString, formatting the text, escaping characters,
244 // and removing whitespace, all while keeping the untranslatable sections and spans in sync with the
245 // transformations.
246 //
247 // Specifically, the StringBuilder will handle escaped characters like \t, \n, \\, \', etc.
248 // Single quotes *must* be escaped, unless within a pair of double-quotes.
249 // Pairs of double-quotes disable whitespace stripping of the enclosed text.
250 // Unicode escape codes (\u0049) are interpreted and the represented Unicode character is inserted.
251 //
252 // A NOTE ON WHITESPACE:
253 //
254 // When preserve_spaces is false, and when text is not enclosed within double-quotes,
255 // StringBuilder replaces a series of whitespace with a single space character. This happens at the
256 // start and end of the string as well, so leading and trailing whitespace is possible.
257 //
258 // When a Span is started or stopped, the whitespace counter is reset, meaning if whitespace
259 // is encountered directly after the span, it will be emitted. This leads to situations like the
260 // following: "This <b> is </b> spaced" -> "This  is  spaced". Without spans, this would be properly
261 // compressed: "This  is  spaced" -> "This is spaced".
262 //
263 // Untranslatable sections do not have the same problem:
264 // "This <xliff:g> is </xliff:g> not spaced" -> "This is not spaced".
265 //
266 // NOTE: This is all the way it is because AAPT1 did it this way. Maintaining backwards
267 // compatibility is important.
268 //
269 class StringBuilder {
270  public:
271   using SpanHandle = size_t;
272   using UntranslatableHandle = size_t;
273 
274   // Creates a StringBuilder. If preserve_spaces is true, whitespace removal is not performed, and
275   // single quotations can be used without escaping them.
276   explicit StringBuilder(bool preserve_spaces = false);
277 
278   // Appends a chunk of text.
279   StringBuilder& AppendText(const std::string& text);
280 
281   // Starts a Span (tag) with the given name. The name is expected to be of the form:
282   //  "tag_name;attr1=value;attr2=value;"
283   // Which is how Spans are encoded in the ResStringPool.
284   // To end the span, pass back the SpanHandle received from this method to the EndSpan() method.
285   SpanHandle StartSpan(const std::string& name);
286 
287   // Ends a Span (tag). Pass in the matching SpanHandle previously obtained from StartSpan().
288   void EndSpan(SpanHandle handle);
289 
290   // Starts an Untranslatable section.
291   // To end the section, pass back the UntranslatableHandle received from this method to
292   // the EndUntranslatable() method.
293   UntranslatableHandle StartUntranslatable();
294 
295   // Ends an Untranslatable section. Pass in the matching UntranslatableHandle previously obtained
296   // from StartUntranslatable().
297   void EndUntranslatable(UntranslatableHandle handle);
298 
299   // Returns the flattened XML string, with all spans and untranslatable sections encoded as
300   // parallel data structures.
301   FlattenedXmlString GetFlattenedString() const;
302 
303   // Returns just the flattened XML text, with no spans or untranslatable sections.
304   std::string to_string() const;
305 
306   // Returns true if there was no error.
307   explicit operator bool() const;
308 
309   std::string GetError() const;
310 
311  private:
312   DISALLOW_COPY_AND_ASSIGN(StringBuilder);
313 
314   void ResetTextState();
315 
316   std::string error_;
317   FlattenedXmlString xml_string_;
318   uint32_t utf16_len_ = 0u;
319   bool preserve_spaces_;
320   bool quote_;
321   bool last_codepoint_was_space_ = false;
322 };
323 
324 }  // namespace ResourceUtils
325 }  // namespace aapt
326 
327 #endif /* AAPT_RESOURCEUTILS_H */
328