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 "androidfw/ResourceTypes.h"
20 
21 #include "Diagnostics.h"
22 #include "ResourceUtils.h"
23 #include "SdkConstants.h"
24 #include "ValueVisitor.h"
25 #include "link/ReferenceLinker.h"
26 #include "process/IResourceTableConsumer.h"
27 #include "process/SymbolTable.h"
28 #include "trace/TraceBuffer.h"
29 #include "util/Util.h"
30 #include "xml/XmlDom.h"
31 
32 namespace aapt {
33 
34 namespace {
35 
36 // Visits all references (including parents of styles, references in styles, arrays, etc) and
37 // links their symbolic name to their Resource ID, performing mangling and package aliasing
38 // as needed.
39 class ReferenceVisitor : public DescendingValueVisitor {
40  public:
41   using DescendingValueVisitor::Visit;
42 
ReferenceVisitor(const CallSite & callsite,IAaptContext * context,SymbolTable * symbols,xml::IPackageDeclStack * decls)43   ReferenceVisitor(const CallSite& callsite, IAaptContext* context, SymbolTable* symbols,
44                    xml::IPackageDeclStack* decls)
45       : callsite_(callsite), context_(context), symbols_(symbols), decls_(decls), error_(false) {}
46 
Visit(Reference * ref)47   void Visit(Reference* ref) override {
48     if (!ReferenceLinker::LinkReference(callsite_, ref, context_, symbols_, decls_)) {
49       error_ = true;
50     }
51   }
52 
HasError() const53   bool HasError() const {
54     return error_;
55   }
56 
57  private:
58   DISALLOW_COPY_AND_ASSIGN(ReferenceVisitor);
59 
60   const CallSite& callsite_;
61   IAaptContext* context_;
62   SymbolTable* symbols_;
63   xml::IPackageDeclStack* decls_;
64   bool error_;
65 };
66 
67 // Visits each xml Element and compiles the attributes within.
68 class XmlVisitor : public xml::PackageAwareVisitor {
69  public:
70   using xml::PackageAwareVisitor::Visit;
71 
XmlVisitor(const Source & source,const CallSite & callsite,IAaptContext * context,SymbolTable * symbols)72   XmlVisitor(const Source& source, const CallSite& callsite, IAaptContext* context,
73              SymbolTable* symbols)
74       : source_(source),
75         callsite_(callsite),
76         context_(context),
77         symbols_(symbols),
78         reference_visitor_(callsite, context, symbols, this) {
79   }
80 
Visit(xml::Element * el)81   void Visit(xml::Element* el) override {
82     // The default Attribute allows everything except enums or flags.
83     Attribute default_attribute(android::ResTable_map::TYPE_ANY);
84     default_attribute.SetWeak(true);
85 
86     // The default orientation of gradients in android Q is different than previous android
87     // versions. Set the android:angle attribute to "0" to ensure that the default gradient
88     // orientation will remain left-to-right in android Q.
89     if (el->name == "gradient" && context_->GetMinSdkVersion() <= SDK_Q) {
90       if (!el->FindAttribute(xml::kSchemaAndroid, "angle")) {
91         el->attributes.push_back(xml::Attribute{xml::kSchemaAndroid, "angle", "0"});
92       }
93     }
94 
95     const Source source = source_.WithLine(el->line_number);
96     for (xml::Attribute& attr : el->attributes) {
97       // If the attribute has no namespace, interpret values as if
98       // they were assigned to the default Attribute.
99 
100       const Attribute* attribute = &default_attribute;
101 
102       if (Maybe<xml::ExtractedPackage> maybe_package =
103               xml::ExtractPackageFromNamespace(attr.namespace_uri)) {
104         // There is a valid package name for this attribute. We will look this up.
105         Reference attr_ref(
106             ResourceNameRef(maybe_package.value().package, ResourceType::kAttr, attr.name));
107         attr_ref.private_reference = maybe_package.value().private_namespace;
108 
109         std::string err_str;
110         attr.compiled_attribute =
111             ReferenceLinker::CompileXmlAttribute(attr_ref, callsite_, context_, symbols_, &err_str);
112 
113         if (!attr.compiled_attribute) {
114           DiagMessage error_msg(source);
115           error_msg << "attribute ";
116           ReferenceLinker::WriteAttributeName(attr_ref, callsite_, this, &error_msg);
117           error_msg << " " << err_str;
118           context_->GetDiagnostics()->Error(error_msg);
119           error_ = true;
120           continue;
121         }
122 
123         attribute = &attr.compiled_attribute.value().attribute;
124       }
125 
126       attr.compiled_value = ResourceUtils::TryParseItemForAttribute(attr.value, attribute);
127       if (attr.compiled_value) {
128         // With a compiledValue, we must resolve the reference and assign it an ID.
129         attr.compiled_value->SetSource(source);
130         attr.compiled_value->Accept(&reference_visitor_);
131       } else if ((attribute->type_mask & android::ResTable_map::TYPE_STRING) == 0) {
132         // We won't be able to encode this as a string.
133         DiagMessage msg(source);
134         msg << "'" << attr.value << "' is incompatible with attribute " << attr.name << " "
135             << *attribute;
136         context_->GetDiagnostics()->Error(msg);
137         error_ = true;
138       }
139     }
140 
141     // Call the super implementation.
142     xml::PackageAwareVisitor::Visit(el);
143   }
144 
HasError()145   bool HasError() {
146     return error_ || reference_visitor_.HasError();
147   }
148 
149  private:
150   DISALLOW_COPY_AND_ASSIGN(XmlVisitor);
151 
152   Source source_;
153   const CallSite& callsite_;
154   IAaptContext* context_;
155   SymbolTable* symbols_;
156 
157   ReferenceVisitor reference_visitor_;
158   bool error_ = false;
159 };
160 
161 }  // namespace
162 
Consume(IAaptContext * context,xml::XmlResource * resource)163 bool XmlReferenceLinker::Consume(IAaptContext* context, xml::XmlResource* resource) {
164   TRACE_NAME("XmlReferenceLinker::Consume");
165   CallSite callsite{resource->file.name.package};
166 
167   std::string out_name = resource->file.name.entry;
168   NameMangler::Unmangle(&out_name, &callsite.package);
169 
170   if (callsite.package.empty()) {
171     // Assume an empty package means that the XML file is local. This is true of AndroidManifest.xml
172     // for example.
173     callsite.package = context->GetCompilationPackage();
174   }
175 
176   XmlVisitor visitor(resource->file.source, callsite, context, context->GetExternalSymbols());
177   if (resource->root) {
178     resource->root->Accept(&visitor);
179     return !visitor.HasError();
180   }
181   return false;
182 }
183 
184 }  // namespace aapt
185