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