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 #include "link/Linkers.h"
18
19 #include <algorithm>
20
21 #include "android-base/logging.h"
22
23 #include "ConfigDescription.h"
24 #include "ResourceTable.h"
25 #include "SdkConstants.h"
26 #include "ValueVisitor.h"
27
28 namespace aapt {
29
ShouldGenerateVersionedResource(const ResourceEntry * entry,const ConfigDescription & config,const ApiVersion sdk_version_to_generate)30 bool ShouldGenerateVersionedResource(const ResourceEntry* entry, const ConfigDescription& config,
31 const ApiVersion sdk_version_to_generate) {
32 // We assume the caller is trying to generate a version greater than the current configuration.
33 CHECK(sdk_version_to_generate > config.sdkVersion);
34 return sdk_version_to_generate < FindNextApiVersionForConfig(entry, config);
35 }
36
FindNextApiVersionForConfig(const ResourceEntry * entry,const ConfigDescription & config)37 ApiVersion FindNextApiVersionForConfig(const ResourceEntry* entry,
38 const ConfigDescription& config) {
39 const auto end_iter = entry->values.end();
40 auto iter = entry->values.begin();
41 for (; iter != end_iter; ++iter) {
42 if ((*iter)->config == config) {
43 break;
44 }
45 }
46
47 // The source config came from this list, so it should be here.
48 CHECK(iter != entry->values.end());
49 ++iter;
50
51 // The next configuration either only varies in sdkVersion, or it is completely different
52 // and therefore incompatible. If it is incompatible, we must generate the versioned resource.
53
54 // NOTE: The ordering of configurations takes sdkVersion as higher precedence than other
55 // qualifiers, so we need to iterate through the entire list to be sure there
56 // are no higher sdk level versions of this resource.
57 ConfigDescription temp_config(config);
58 for (; iter != end_iter; ++iter) {
59 temp_config.sdkVersion = (*iter)->config.sdkVersion;
60 if (temp_config == (*iter)->config) {
61 // The two configs are the same, return the sdkVersion.
62 return (*iter)->config.sdkVersion;
63 }
64 }
65
66 // Didn't find another config with a different sdk version, so return the highest possible value.
67 return std::numeric_limits<ApiVersion>::max();
68 }
69
Consume(IAaptContext * context,ResourceTable * table)70 bool AutoVersioner::Consume(IAaptContext* context, ResourceTable* table) {
71 for (auto& package : table->packages) {
72 for (auto& type : package->types) {
73 if (type->type != ResourceType::kStyle) {
74 continue;
75 }
76
77 for (auto& entry : type->entries) {
78 for (size_t i = 0; i < entry->values.size(); i++) {
79 ResourceConfigValue* config_value = entry->values[i].get();
80 if (config_value->config.sdkVersion >= SDK_LOLLIPOP_MR1) {
81 // If this configuration is only used on L-MR1 then we don't need
82 // to do anything since we use private attributes since that
83 // version.
84 continue;
85 }
86
87 if (Style* style = ValueCast<Style>(config_value->value.get())) {
88 Maybe<ApiVersion> min_sdk_stripped;
89 std::vector<Style::Entry> stripped;
90
91 auto iter = style->entries.begin();
92 while (iter != style->entries.end()) {
93 CHECK(bool(iter->key.id)) << "IDs must be assigned and linked";
94
95 // Find the SDK level that is higher than the configuration
96 // allows.
97 const ApiVersion sdk_level = FindAttributeSdkLevel(iter->key.id.value());
98 if (sdk_level > std::max<ApiVersion>(config_value->config.sdkVersion, 1)) {
99 // Record that we are about to strip this.
100 stripped.emplace_back(std::move(*iter));
101
102 // We use the smallest SDK level to generate the new style.
103 if (min_sdk_stripped) {
104 min_sdk_stripped = std::min(min_sdk_stripped.value(), sdk_level);
105 } else {
106 min_sdk_stripped = sdk_level;
107 }
108
109 // Erase this from this style.
110 iter = style->entries.erase(iter);
111 continue;
112 }
113 ++iter;
114 }
115
116 if (min_sdk_stripped && !stripped.empty()) {
117 // We found attributes from a higher SDK level. Check that
118 // there is no other defined resource for the version we want to
119 // generate.
120 if (ShouldGenerateVersionedResource(entry.get(),
121 config_value->config,
122 min_sdk_stripped.value())) {
123 // Let's create a new Style for this versioned resource.
124 ConfigDescription new_config(config_value->config);
125 new_config.sdkVersion = static_cast<uint16_t>(min_sdk_stripped.value());
126
127 std::unique_ptr<Style> new_style(style->Clone(&table->string_pool));
128 new_style->SetComment(style->GetComment());
129 new_style->SetSource(style->GetSource());
130
131 // Move the previously stripped attributes into this style.
132 new_style->entries.insert(
133 new_style->entries.end(),
134 std::make_move_iterator(stripped.begin()),
135 std::make_move_iterator(stripped.end()));
136
137 // Insert the new Resource into the correct place.
138 entry->FindOrCreateValue(new_config, {})->value = std::move(new_style);
139 }
140 }
141 }
142 }
143 }
144 }
145 }
146 return true;
147 }
148
149 } // namespace aapt
150