[view compiler] Add XML to DEX compilation

Test: atest
Bug: 111895153
Change-Id: I91c01ff4474e080c87b902ae963b5d655346f859

1 files changed, 118 insertions, 0 deletions

diff --git a/startop/view_compiler/dex_layout_compiler.h b/startop/view_compiler/dex_layout_compiler.h
new file mode 100644
index 000000000000..170a1a610297
--- /dev/null
+++ b/startop/view_compiler/dex_layout_compiler.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DEX_LAYOUT_COMPILER_H_
+#define DEX_LAYOUT_COMPILER_H_
+
+#include "dex_builder.h"
+
+#include <codecvt>
+#include <locale>
+#include <string>
+#include <vector>
+
+namespace startop {
+
+// This visitor does the actual view compilation, using a supplied builder.
+template <typename Builder>
+class LayoutCompilerVisitor {
+ public:
+  explicit LayoutCompilerVisitor(Builder* builder) : builder_{builder} {}
+
+  void VisitStartDocument() { builder_->Start(); }
+  void VisitEndDocument() { builder_->Finish(); }
+  void VisitStartTag(const std::u16string& name) {
+    parent_stack_.push_back(ViewEntry{
+        std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>{}.to_bytes(name), {}});
+  }
+  void VisitEndTag() {
+    auto entry = parent_stack_.back();
+    parent_stack_.pop_back();
+
+    if (parent_stack_.empty()) {
+      GenerateCode(entry);
+    } else {
+      parent_stack_.back().children.push_back(entry);
+    }
+  }
+
+ private:
+  struct ViewEntry {
+    std::string name;
+    std::vector<ViewEntry> children;
+  };
+
+  void GenerateCode(const ViewEntry& view) {
+    builder_->StartView(view.name, !view.children.empty());
+    for (const auto& child : view.children) {
+      GenerateCode(child);
+    }
+    builder_->FinishView();
+  }
+
+  Builder* builder_;
+
+  std::vector<ViewEntry> parent_stack_;
+};
+
+class DexViewBuilder {
+ public:
+  DexViewBuilder(dex::MethodBuilder* method);
+
+  void Start();
+  void Finish();
+  void StartView(const std::string& name, bool is_viewgroup);
+  void FinishView();
+
+ private:
+  // Accessors for the stack of views that are under construction.
+  dex::Value AcquireRegister();
+  void ReleaseRegister();
+  dex::Value GetCurrentView() const;
+  dex::Value GetCurrentLayoutParams() const;
+  dex::Value GetParentView() const;
+  void PopViewStack();
+
+  dex::MethodBuilder* method_;
+
+  // Registers used for code generation
+  dex::Value const context_;
+  dex::Value const resid_;
+  const dex::Value inflater_;
+  const dex::Value xml_;
+  const dex::Value attrs_;
+  const dex::Value classname_tmp_;
+
+  const dex::MethodDeclData xml_next_;
+  const dex::MethodDeclData try_create_view_;
+  const dex::MethodDeclData generate_layout_params_;
+  const dex::MethodDeclData add_view_;
+
+  // used for keeping track of which registers are in use
+  size_t top_register_{0};
+  std::vector<dex::Value> register_stack_;
+
+  // Keep track of the views currently in progress.
+  struct ViewEntry {
+    dex::Value view;
+    std::optional<dex::Value> layout_params;
+  };
+  std::vector<ViewEntry> view_stack_;
+};
+
+}  // namespace startop
+
+#endif  // DEX_LAYOUT_COMPILER_H_