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_NAME_MANGLER_H
18 #define AAPT_NAME_MANGLER_H
19 
20 #include <set>
21 #include <string>
22 
23 #include "Resource.h"
24 #include "util/Maybe.h"
25 
26 namespace aapt {
27 
28 struct NameManglerPolicy {
29   /**
30    * Represents the package we are trying to build. References pointing
31    * to this package are not mangled, and mangled references inherit this
32    * package name.
33    */
34   std::string target_package_name;
35 
36   /**
37    * We must know which references to mangle, and which to keep (android vs.
38    * com.android.support).
39    */
40   std::set<std::string> packages_to_mangle;
41 };
42 
43 class NameMangler {
44  public:
NameMangler(NameManglerPolicy policy)45   explicit NameMangler(NameManglerPolicy policy) : policy_(policy) {}
46 
MangleName(const ResourceName & name)47   Maybe<ResourceName> MangleName(const ResourceName& name) {
48     if (policy_.target_package_name == name.package ||
49         policy_.packages_to_mangle.count(name.package) == 0) {
50       return {};
51     }
52 
53     std::string mangled_entry_name = MangleEntry(name.package, name.entry);
54     return ResourceName(policy_.target_package_name, name.type,
55                         mangled_entry_name);
56   }
57 
ShouldMangle(const std::string & package)58   bool ShouldMangle(const std::string& package) const {
59     if (package.empty() || policy_.target_package_name == package) {
60       return false;
61     }
62     return policy_.packages_to_mangle.count(package) != 0;
63   }
64 
GetTargetPackageName()65   const std::string& GetTargetPackageName() const { return policy_.target_package_name; }
66 
67   /**
68    * Returns a mangled name that is a combination of `name` and `package`.
69    * The mangled name should contain symbols that are illegal to define in XML,
70    * so that there will never be name mangling collisions.
71    */
MangleEntry(const std::string & package,const std::string & name)72   static std::string MangleEntry(const std::string& package, const std::string& name) {
73     return package + "$" + name;
74   }
75 
76   /**
77    * Unmangles the name in `outName`, storing the correct name back in `outName`
78    * and the package in `outPackage`. Returns true if the name was unmangled or
79    * false if the name was never mangled to begin with.
80    */
Unmangle(std::string * out_name,std::string * out_package)81   static bool Unmangle(std::string* out_name, std::string* out_package) {
82     size_t pivot = out_name->find('$');
83     if (pivot == std::string::npos) {
84       return false;
85     }
86 
87     out_package->assign(out_name->data(), pivot);
88     std::string new_name = out_name->substr(pivot + 1);
89     *out_name = std::move(new_name);
90     return true;
91   }
92 
93  private:
94   NameManglerPolicy policy_;
95 };
96 
97 }  // namespace aapt
98 
99 #endif  // AAPT_NAME_MANGLER_H
100