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      1 /*
      2  * Copyright (C) 2018 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 "dex_layout_compiler.h"
     18 #include "layout_validation.h"
     19 
     20 #include "android-base/stringprintf.h"
     21 
     22 namespace startop {
     23 
     24 using android::base::StringPrintf;
     25 
     26 void LayoutValidationVisitor::VisitStartTag(const std::u16string& name) {
     27   if (0 == name.compare(u"merge")) {
     28     message_ = "Merge tags are not supported";
     29     can_compile_ = false;
     30   }
     31   if (0 == name.compare(u"include")) {
     32     message_ = "Include tags are not supported";
     33     can_compile_ = false;
     34   }
     35   if (0 == name.compare(u"view")) {
     36     message_ = "View tags are not supported";
     37     can_compile_ = false;
     38   }
     39   if (0 == name.compare(u"fragment")) {
     40     message_ = "Fragment tags are not supported";
     41     can_compile_ = false;
     42   }
     43 }
     44 
     45 DexViewBuilder::DexViewBuilder(dex::MethodBuilder* method)
     46     : method_{method},
     47       context_{dex::Value::Parameter(0)},
     48       resid_{dex::Value::Parameter(1)},
     49       inflater_{method->MakeRegister()},
     50       xml_{method->MakeRegister()},
     51       attrs_{method->MakeRegister()},
     52       classname_tmp_{method->MakeRegister()},
     53       xml_next_{method->dex_file()->GetOrDeclareMethod(
     54           dex::TypeDescriptor::FromClassname("android.content.res.XmlResourceParser"), "next",
     55           dex::Prototype{dex::TypeDescriptor::Int()})},
     56       try_create_view_{method->dex_file()->GetOrDeclareMethod(
     57           dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"), "tryCreateView",
     58           dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.View"),
     59                          dex::TypeDescriptor::FromClassname("android.view.View"),
     60                          dex::TypeDescriptor::FromClassname("java.lang.String"),
     61                          dex::TypeDescriptor::FromClassname("android.content.Context"),
     62                          dex::TypeDescriptor::FromClassname("android.util.AttributeSet")})},
     63       generate_layout_params_{method->dex_file()->GetOrDeclareMethod(
     64           dex::TypeDescriptor::FromClassname("android.view.ViewGroup"), "generateLayoutParams",
     65           dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.ViewGroup$LayoutParams"),
     66                          dex::TypeDescriptor::FromClassname("android.util.AttributeSet")})},
     67       add_view_{method->dex_file()->GetOrDeclareMethod(
     68           dex::TypeDescriptor::FromClassname("android.view.ViewGroup"), "addView",
     69           dex::Prototype{
     70               dex::TypeDescriptor::Void(),
     71               dex::TypeDescriptor::FromClassname("android.view.View"),
     72               dex::TypeDescriptor::FromClassname("android.view.ViewGroup$LayoutParams")})},
     73       // The register stack starts with one register, which will be null for the root view.
     74       register_stack_{{method->MakeRegister()}} {}
     75 
     76 void DexViewBuilder::Start() {
     77   dex::DexBuilder* const dex = method_->dex_file();
     78 
     79   // LayoutInflater inflater = LayoutInflater.from(context);
     80   auto layout_inflater_from = dex->GetOrDeclareMethod(
     81       dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"),
     82       "from",
     83       dex::Prototype{dex::TypeDescriptor::FromClassname("android.view.LayoutInflater"),
     84                      dex::TypeDescriptor::FromClassname("android.content.Context")});
     85   method_->AddInstruction(
     86       dex::Instruction::InvokeStaticObject(layout_inflater_from.id, /*dest=*/inflater_, context_));
     87 
     88   // Resources res = context.getResources();
     89   auto context_type = dex::TypeDescriptor::FromClassname("android.content.Context");
     90   auto resources_type = dex::TypeDescriptor::FromClassname("android.content.res.Resources");
     91   auto get_resources =
     92       dex->GetOrDeclareMethod(context_type, "getResources", dex::Prototype{resources_type});
     93   method_->AddInstruction(dex::Instruction::InvokeVirtualObject(get_resources.id, xml_, context_));
     94 
     95   // XmlResourceParser xml = res.getLayout(resid);
     96   auto xml_resource_parser_type =
     97       dex::TypeDescriptor::FromClassname("android.content.res.XmlResourceParser");
     98   auto get_layout =
     99       dex->GetOrDeclareMethod(resources_type,
    100                               "getLayout",
    101                               dex::Prototype{xml_resource_parser_type, dex::TypeDescriptor::Int()});
    102   method_->AddInstruction(dex::Instruction::InvokeVirtualObject(get_layout.id, xml_, xml_, resid_));
    103 
    104   // AttributeSet attrs = Xml.asAttributeSet(xml);
    105   auto as_attribute_set = dex->GetOrDeclareMethod(
    106       dex::TypeDescriptor::FromClassname("android.util.Xml"),
    107       "asAttributeSet",
    108       dex::Prototype{dex::TypeDescriptor::FromClassname("android.util.AttributeSet"),
    109                      dex::TypeDescriptor::FromClassname("org.xmlpull.v1.XmlPullParser")});
    110   method_->AddInstruction(dex::Instruction::InvokeStaticObject(as_attribute_set.id, attrs_, xml_));
    111 
    112   // xml.next(); // start document
    113   method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
    114 }
    115 
    116 void DexViewBuilder::Finish() {}
    117 
    118 namespace {
    119 std::string ResolveName(const std::string& name) {
    120   if (name == "View") return "android.view.View";
    121   if (name == "ViewGroup") return "android.view.ViewGroup";
    122   if (name.find(".") == std::string::npos) {
    123     return StringPrintf("android.widget.%s", name.c_str());
    124   }
    125   return name;
    126 }
    127 }  // namespace
    128 
    129 void DexViewBuilder::StartView(const std::string& name, bool is_viewgroup) {
    130   bool const is_root_view = view_stack_.empty();
    131 
    132   // xml.next(); // start tag
    133   method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
    134 
    135   dex::Value view = AcquireRegister();
    136   // try to create the view using the factories
    137   method_->BuildConstString(classname_tmp_,
    138                             name);  // TODO: the need to fully qualify the classname
    139   if (is_root_view) {
    140     dex::Value null = AcquireRegister();
    141     method_->BuildConst4(null, 0);
    142     method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
    143         try_create_view_.id, view, inflater_, null, classname_tmp_, context_, attrs_));
    144     ReleaseRegister();
    145   } else {
    146     method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
    147         try_create_view_.id, view, inflater_, GetCurrentView(), classname_tmp_, context_, attrs_));
    148   }
    149   auto label = method_->MakeLabel();
    150   // branch if not null
    151   method_->AddInstruction(
    152       dex::Instruction::OpWithArgs(dex::Instruction::Op::kBranchNEqz, /*dest=*/{}, view, label));
    153 
    154   // If null, create the class directly.
    155   method_->BuildNew(view,
    156                     dex::TypeDescriptor::FromClassname(ResolveName(name)),
    157                     dex::Prototype{dex::TypeDescriptor::Void(),
    158                                    dex::TypeDescriptor::FromClassname("android.content.Context"),
    159                                    dex::TypeDescriptor::FromClassname("android.util.AttributeSet")},
    160                     context_,
    161                     attrs_);
    162 
    163   method_->AddInstruction(
    164       dex::Instruction::OpWithArgs(dex::Instruction::Op::kBindLabel, /*dest=*/{}, label));
    165 
    166   if (is_viewgroup) {
    167     // Cast to a ViewGroup so we can add children later.
    168     const ir::Type* view_group_def = method_->dex_file()->GetOrAddType(
    169         dex::TypeDescriptor::FromClassname("android.view.ViewGroup").descriptor());
    170     method_->AddInstruction(dex::Instruction::Cast(view, dex::Value::Type(view_group_def->orig_index)));
    171   }
    172 
    173   if (!is_root_view) {
    174     // layout_params = parent.generateLayoutParams(attrs);
    175     dex::Value layout_params{AcquireRegister()};
    176     method_->AddInstruction(dex::Instruction::InvokeVirtualObject(
    177         generate_layout_params_.id, layout_params, GetCurrentView(), attrs_));
    178     view_stack_.push_back({view, layout_params});
    179   } else {
    180     view_stack_.push_back({view, {}});
    181   }
    182 }
    183 
    184 void DexViewBuilder::FinishView() {
    185   if (view_stack_.size() == 1) {
    186     method_->BuildReturn(GetCurrentView(), /*is_object=*/true);
    187   } else {
    188     // parent.add(view, layout_params)
    189     method_->AddInstruction(dex::Instruction::InvokeVirtual(
    190         add_view_.id, /*dest=*/{}, GetParentView(), GetCurrentView(), GetCurrentLayoutParams()));
    191     // xml.next(); // end tag
    192     method_->AddInstruction(dex::Instruction::InvokeInterface(xml_next_.id, {}, xml_));
    193   }
    194   PopViewStack();
    195 }
    196 
    197 dex::Value DexViewBuilder::AcquireRegister() {
    198   top_register_++;
    199   if (register_stack_.size() == top_register_) {
    200     register_stack_.push_back(method_->MakeRegister());
    201   }
    202   return register_stack_[top_register_];
    203 }
    204 
    205 void DexViewBuilder::ReleaseRegister() { top_register_--; }
    206 
    207 dex::Value DexViewBuilder::GetCurrentView() const { return view_stack_.back().view; }
    208 dex::Value DexViewBuilder::GetCurrentLayoutParams() const {
    209   return view_stack_.back().layout_params.value();
    210 }
    211 dex::Value DexViewBuilder::GetParentView() const {
    212   return view_stack_[view_stack_.size() - 2].view;
    213 }
    214 
    215 void DexViewBuilder::PopViewStack() {
    216   const auto& top = view_stack_.back();
    217   // release the layout params if we have them
    218   if (top.layout_params.has_value()) {
    219     ReleaseRegister();
    220   }
    221   // Unconditionally release the view register.
    222   ReleaseRegister();
    223   view_stack_.pop_back();
    224 }
    225 
    226 }  // namespace startop