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