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1 /*
2  * Copyright (C) 2016 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_XML_XMLPATTERN_H
18 #define AAPT_XML_XMLPATTERN_H
19 
20 #include <functional>
21 #include <map>
22 #include <string>
23 #include <vector>
24 
25 #include "android-base/macros.h"
26 
27 #include "Diagnostics.h"
28 #include "xml/XmlDom.h"
29 
30 namespace aapt {
31 namespace xml {
32 
33 enum class XmlActionExecutorPolicy {
34   // Actions are run if elements are matched, errors occur only when actions return false.
35   kNone,
36 
37   // The actions defined must match and run. If an element is found that does not match an action,
38   // an error occurs.
39   // Note: namespaced elements are always ignored.
40   kAllowList,
41 
42   // The actions defined should match and run. if an element is found that does not match an
43   // action, a warning is printed.
44   // Note: namespaced elements are always ignored.
45   kAllowListWarning,
46 };
47 
48 // Contains the actions to perform at this XML node. This is a recursive data structure that
49 // holds XmlNodeActions for child XML nodes.
50 class XmlNodeAction {
51  public:
52   using ActionFuncWithPolicyAndDiag =
53       std::function<bool(Element*, XmlActionExecutorPolicy, SourcePathDiagnostics*)>;
54   using ActionFuncWithDiag = std::function<bool(Element*, SourcePathDiagnostics*)>;
55   using ActionFunc = std::function<bool(Element*)>;
56 
57   // Find or create a child XmlNodeAction that will be performed for the child element with the
58   // name `name`.
59   XmlNodeAction& operator[](const std::string& name) {
60     return map_[name];
61   }
62 
63   // Add an action to be performed at this XmlNodeAction.
64   void Action(ActionFunc f);
65   void Action(ActionFuncWithDiag);
66   void Action(ActionFuncWithPolicyAndDiag);
67 
68  private:
69   friend class XmlActionExecutor;
70 
71   bool Execute(XmlActionExecutorPolicy policy, std::vector<::android::StringPiece>* bread_crumb,
72                SourcePathDiagnostics* diag, Element* el) const;
73 
74   std::map<std::string, XmlNodeAction> map_;
75   std::vector<ActionFuncWithPolicyAndDiag> actions_;
76 };
77 
78 // Allows the definition of actions to execute at specific XML elements defined by their hierarchy.
79 class XmlActionExecutor {
80  public:
81   XmlActionExecutor() = default;
82 
83   // Find or create a root XmlNodeAction that will be performed for the root XML element with the
84   // name `name`.
85   XmlNodeAction& operator[](const std::string& name) {
86     return map_[name];
87   }
88 
89   // Execute the defined actions for this XmlResource.
90   // Returns true if all actions return true, otherwise returns false.
91   bool Execute(XmlActionExecutorPolicy policy, IDiagnostics* diag, XmlResource* doc) const;
92 
93  private:
94   std::map<std::string, XmlNodeAction> map_;
95 
96   DISALLOW_COPY_AND_ASSIGN(XmlActionExecutor);
97 };
98 
99 }  // namespace xml
100 }  // namespace aapt
101 
102 #endif /* AAPT_XML_XMLPATTERN_H */
103