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 #include "optimize/ResourceDeduper.h"
18
19 #include <algorithm>
20
21 #include "DominatorTree.h"
22 #include "ResourceTable.h"
23
24 namespace aapt {
25
26 namespace {
27
28 /**
29 * Remove duplicated key-value entries from dominated resources.
30 *
31 * Based on the dominator tree, we can remove a value of an entry if:
32 *
33 * 1. The configuration for the entry's value is dominated by a configuration
34 * with an equivalent entry value.
35 * 2. All compatible configurations for the entry (those not in conflict and
36 * unrelated by domination with the configuration for the entry's value) have
37 * an equivalent entry value.
38 */
39 class DominatedKeyValueRemover : public DominatorTree::BottomUpVisitor {
40 public:
41 using Node = DominatorTree::Node;
42
DominatedKeyValueRemover(IAaptContext * context,ResourceEntry * entry)43 explicit DominatedKeyValueRemover(IAaptContext* context, ResourceEntry* entry)
44 : context_(context), entry_(entry) {}
45
VisitConfig(Node * node)46 void VisitConfig(Node* node) {
47 Node* parent = node->parent();
48 if (!parent) {
49 return;
50 }
51 ResourceConfigValue* node_value = node->value();
52 ResourceConfigValue* parent_value = parent->value();
53 if (!node_value || !parent_value) {
54 return;
55 }
56 if (!node_value->value->Equals(parent_value->value.get())) {
57 return;
58 }
59
60 // Compare compatible configs for this entry and ensure the values are
61 // equivalent.
62 const ConfigDescription& node_configuration = node_value->config;
63 for (const auto& sibling : entry_->values) {
64 if (!sibling->value) {
65 // Sibling was already removed.
66 continue;
67 }
68 if (node_configuration.IsCompatibleWith(sibling->config) &&
69 !node_value->value->Equals(sibling->value.get())) {
70 // The configurations are compatible, but the value is
71 // different, so we can't remove this value.
72 return;
73 }
74 }
75 if (context_->IsVerbose()) {
76 context_->GetDiagnostics()->Note(
77 DiagMessage(node_value->value->GetSource())
78 << "removing dominated duplicate resource with name \""
79 << entry_->name << "\"");
80 context_->GetDiagnostics()->Note(
81 DiagMessage(parent_value->value->GetSource()) << "dominated here");
82 }
83 node_value->value = {};
84 }
85
86 private:
87 DISALLOW_COPY_AND_ASSIGN(DominatedKeyValueRemover);
88
89 IAaptContext* context_;
90 ResourceEntry* entry_;
91 };
92
DedupeEntry(IAaptContext * context,ResourceEntry * entry)93 static void DedupeEntry(IAaptContext* context, ResourceEntry* entry) {
94 DominatorTree tree(entry->values);
95 DominatedKeyValueRemover remover(context, entry);
96 tree.Accept(&remover);
97
98 // Erase the values that were removed.
99 entry->values.erase(
100 std::remove_if(
101 entry->values.begin(), entry->values.end(),
102 [](const std::unique_ptr<ResourceConfigValue>& val) -> bool {
103 return val == nullptr || val->value == nullptr;
104 }),
105 entry->values.end());
106 }
107
108 } // namespace
109
Consume(IAaptContext * context,ResourceTable * table)110 bool ResourceDeduper::Consume(IAaptContext* context, ResourceTable* table) {
111 for (auto& package : table->packages) {
112 for (auto& type : package->types) {
113 for (auto& entry : type->entries) {
114 DedupeEntry(context, entry.get());
115 }
116 }
117 }
118 return true;
119 }
120
121 } // namespace aapt
122