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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 Maybe<ResourceName> ToResourceName(
79     const android::ResTable::resource_name& name);
80 
81 /**
82  * Convert an android::AssetManager2::ResourceName to an aapt::ResourceName struct.
83  */
84 Maybe<ResourceName> ToResourceName(
85     const android::AssetManager2::ResourceName& name_in);
86 
87 /**
88  * Returns a boolean value if the string is equal to TRUE, true, True, FALSE,
89  * false, or False.
90  */
91 Maybe<bool> ParseBool(const android::StringPiece& str);
92 
93 /**
94  * Returns a uint32_t if the string is an integer.
95  */
96 Maybe<uint32_t> ParseInt(const android::StringPiece& str);
97 
98 /**
99  * Returns an ID if it the string represented a valid ID.
100  */
101 Maybe<ResourceId> ParseResourceId(const android::StringPiece& str);
102 
103 /**
104  * Parses an SDK version, which can be an integer, or a letter from A-Z.
105  */
106 Maybe<int> ParseSdkVersion(const android::StringPiece& str);
107 
108 /*
109  * Returns a Reference, or None Maybe instance if the string `str` was parsed as
110  * a
111  * valid reference to a style.
112  * The format for a style parent is slightly more flexible than a normal
113  * reference:
114  *
115  * @[package:]style/<entry> or
116  * ?[package:]style/<entry> or
117  * <package>:[style/]<entry>
118  */
119 Maybe<Reference> ParseStyleParentReference(const android::StringPiece& str, std::string* out_error);
120 
121 /*
122  * Returns a Reference if the string `str` was parsed as a valid XML attribute
123  * name.
124  * The valid format for an XML attribute name is:
125  *
126  * package:entry
127  */
128 Maybe<Reference> ParseXmlAttributeName(const android::StringPiece& str);
129 
130 /*
131  * Returns a Reference object if the string was parsed as a resource or
132  * attribute reference,
133  * ( @[+][package:]type/name | ?[package:]type/name ) setting outCreate to true
134  * if
135  * the '+' was present in the string.
136  */
137 std::unique_ptr<Reference> TryParseReference(const android::StringPiece& str,
138                                              bool* out_create = nullptr);
139 
140 /*
141  * Returns a BinaryPrimitve object representing @null or @empty if the string
142  * was parsed as one.
143  */
144 std::unique_ptr<Item> TryParseNullOrEmpty(const android::StringPiece& str);
145 
146 // Returns a Reference representing @null.
147 // Due to runtime compatibility issues, this is encoded as a reference with ID 0.
148 // The runtime will convert this to TYPE_NULL.
149 std::unique_ptr<Reference> MakeNull();
150 
151 // Returns a BinaryPrimitive representing @empty. This is encoded as a Res_value with
152 // type Res_value::TYPE_NULL and data Res_value::DATA_NULL_EMPTY.
153 std::unique_ptr<BinaryPrimitive> MakeEmpty();
154 
155 /*
156  * Returns a BinaryPrimitve object representing a color if the string was parsed
157  * as one.
158  */
159 std::unique_ptr<BinaryPrimitive> TryParseColor(const android::StringPiece& str);
160 
161 /*
162  * Returns a BinaryPrimitve object representing a boolean if the string was
163  * parsed as one.
164  */
165 std::unique_ptr<BinaryPrimitive> TryParseBool(const android::StringPiece& str);
166 
167 // Returns a boolean BinaryPrimitive.
168 std::unique_ptr<BinaryPrimitive> MakeBool(bool val);
169 
170 /*
171  * Returns a BinaryPrimitve object representing an integer if the string was
172  * parsed as one.
173  */
174 std::unique_ptr<BinaryPrimitive> TryParseInt(const android::StringPiece& str);
175 
176 // Returns an integer BinaryPrimitive.
177 std::unique_ptr<BinaryPrimitive> MakeInt(uint32_t value);
178 
179 /*
180  * Returns a BinaryPrimitve object representing a floating point number
181  * (float, dimension, etc) if the string was parsed as one.
182  */
183 std::unique_ptr<BinaryPrimitive> TryParseFloat(const android::StringPiece& str);
184 
185 /*
186  * Returns a BinaryPrimitve object representing an enum symbol if the string was
187  * parsed as one.
188  */
189 std::unique_ptr<BinaryPrimitive> TryParseEnumSymbol(const Attribute* enum_attr,
190                                                     const android::StringPiece& str);
191 
192 /*
193  * Returns a BinaryPrimitve object representing a flag symbol if the string was
194  * parsed as one.
195  */
196 std::unique_ptr<BinaryPrimitive> TryParseFlagSymbol(const Attribute* enum_attr,
197                                                     const android::StringPiece& str);
198 /*
199  * Try to convert a string to an Item for the given attribute. The attribute
200  * will
201  * restrict what values the string can be converted to.
202  * The callback function on_create_reference is called when the parsed item is a
203  * reference to an ID that must be created (@+id/foo).
204  */
205 std::unique_ptr<Item> TryParseItemForAttribute(
206     const android::StringPiece& value, const Attribute* attr,
207     const std::function<void(const ResourceName&)>& on_create_reference = {});
208 
209 std::unique_ptr<Item> TryParseItemForAttribute(
210     const android::StringPiece& value, uint32_t type_mask,
211     const std::function<void(const ResourceName&)>& on_create_reference = {});
212 
213 uint32_t AndroidTypeToAttributeTypeMask(uint16_t type);
214 
215 /**
216  * Returns a string path suitable for use within an APK. The path will look
217  * like:
218  *
219  * res/type[-config]/<name>.<ext>
220  *
221  * Then name may be mangled if a NameMangler is supplied (can be nullptr) and
222  * the package
223  * requires mangling.
224  */
225 std::string BuildResourceFileName(const ResourceFile& res_file,
226                                   const NameMangler* mangler = nullptr);
227 
228 // Parses the binary form of a resource value. `type` is used as a hint to know when a value is
229 // an ID versus a False boolean value, etc. `config` is for sorting strings in the string pool.
230 std::unique_ptr<Item> ParseBinaryResValue(const ResourceType& type,
231                                           const android::ConfigDescription& config,
232                                           const android::ResStringPool& src_pool,
233                                           const android::Res_value& res_value,
234                                           StringPool* dst_pool);
235 
236 // A string flattened from an XML hierarchy, which maintains tags and untranslatable sections
237 // in parallel data structures.
238 struct FlattenedXmlString {
239   std::string text;
240   std::vector<UntranslatableSection> untranslatable_sections;
241   std::vector<Span> spans;
242 };
243 
244 // Flattens an XML hierarchy into a FlattenedXmlString, formatting the text, escaping characters,
245 // and removing whitespace, all while keeping the untranslatable sections and spans in sync with the
246 // transformations.
247 //
248 // Specifically, the StringBuilder will handle escaped characters like \t, \n, \\, \', etc.
249 // Single quotes *must* be escaped, unless within a pair of double-quotes.
250 // Pairs of double-quotes disable whitespace stripping of the enclosed text.
251 // Unicode escape codes (\u0049) are interpreted and the represented Unicode character is inserted.
252 //
253 // A NOTE ON WHITESPACE:
254 //
255 // When preserve_spaces is false, and when text is not enclosed within double-quotes,
256 // StringBuilder replaces a series of whitespace with a single space character. This happens at the
257 // start and end of the string as well, so leading and trailing whitespace is possible.
258 //
259 // When a Span is started or stopped, the whitespace counter is reset, meaning if whitespace
260 // is encountered directly after the span, it will be emitted. This leads to situations like the
261 // following: "This <b> is </b> spaced" -> "This  is  spaced". Without spans, this would be properly
262 // compressed: "This  is  spaced" -> "This is spaced".
263 //
264 // Untranslatable sections do not have the same problem:
265 // "This <xliff:g> is </xliff:g> not spaced" -> "This is not spaced".
266 //
267 // NOTE: This is all the way it is because AAPT1 did it this way. Maintaining backwards
268 // compatibility is important.
269 //
270 class StringBuilder {
271  public:
272   using SpanHandle = size_t;
273   using UntranslatableHandle = size_t;
274 
275   // Creates a StringBuilder. If preserve_spaces is true, whitespace removal is not performed, and
276   // single quotations can be used without escaping them.
277   explicit StringBuilder(bool preserve_spaces = false);
278 
279   // Appends a chunk of text.
280   StringBuilder& AppendText(const std::string& text);
281 
282   // Starts a Span (tag) with the given name. The name is expected to be of the form:
283   //  "tag_name;attr1=value;attr2=value;"
284   // Which is how Spans are encoded in the ResStringPool.
285   // To end the span, pass back the SpanHandle received from this method to the EndSpan() method.
286   SpanHandle StartSpan(const std::string& name);
287 
288   // Ends a Span (tag). Pass in the matching SpanHandle previously obtained from StartSpan().
289   void EndSpan(SpanHandle handle);
290 
291   // Starts an Untranslatable section.
292   // To end the section, pass back the UntranslatableHandle received from this method to
293   // the EndUntranslatable() method.
294   UntranslatableHandle StartUntranslatable();
295 
296   // Ends an Untranslatable section. Pass in the matching UntranslatableHandle previously obtained
297   // from StartUntranslatable().
298   void EndUntranslatable(UntranslatableHandle handle);
299 
300   // Returns the flattened XML string, with all spans and untranslatable sections encoded as
301   // parallel data structures.
302   FlattenedXmlString GetFlattenedString() const;
303 
304   // Returns just the flattened XML text, with no spans or untranslatable sections.
305   std::string to_string() const;
306 
307   // Returns true if there was no error.
308   explicit operator bool() const;
309 
310   std::string GetError() const;
311 
312  private:
313   DISALLOW_COPY_AND_ASSIGN(StringBuilder);
314 
315   void ResetTextState();
316 
317   std::string error_;
318   FlattenedXmlString xml_string_;
319   uint32_t utf16_len_ = 0u;
320   bool preserve_spaces_;
321   bool quote_;
322   bool last_codepoint_was_space_ = false;
323 };
324 
325 }  // namespace ResourceUtils
326 }  // namespace aapt
327 
328 #endif /* AAPT_RESOURCEUTILS_H */
329