Merge "Prototype XML view compiler"
am: 956791cee8
Change-Id: I879bfc0b0755b22c1653a3d06dedc890c6c4b8a6
diff --git a/startop/tools/view_compiler/Android.bp b/startop/tools/view_compiler/Android.bp
new file mode 100644
index 0000000..c3e9184
--- /dev/null
+++ b/startop/tools/view_compiler/Android.bp
@@ -0,0 +1,49 @@
+//
+// 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.
+//
+
+cc_library_host_static {
+ name: "libviewcompiler",
+ srcs: [
+ "java_lang_builder.cc",
+ "util.cc",
+ ],
+ static_libs: [
+ "libbase"
+ ]
+}
+
+cc_binary_host {
+ name: "viewcompiler",
+ srcs: [
+ "main.cc",
+ ],
+ static_libs: [
+ "libbase",
+ "libtinyxml2",
+ "libgflags",
+ "libviewcompiler",
+ ],
+}
+
+cc_test_host {
+ name: "view-compiler-tests",
+ srcs: [
+ "util_test.cc",
+ ],
+ static_libs: [
+ "libviewcompiler",
+ ]
+}
diff --git a/startop/tools/view_compiler/README.md b/startop/tools/view_compiler/README.md
new file mode 100644
index 0000000..5659501
--- /dev/null
+++ b/startop/tools/view_compiler/README.md
@@ -0,0 +1,25 @@
+# View Compiler
+
+This directory contains an experimental compiler for layout files.
+
+It will take a layout XML file and produce a CompiledLayout.java file with a
+specialized layout inflation function.
+
+To use it, let's assume you had a layout in `my_layout.xml` and your app was in
+the Java language package `com.example.myapp`. Run the following command:
+
+ viewcompiler my_layout.xml --package com.example.myapp --out CompiledView.java
+
+This will produce a `CompiledView.java`, which can then be compiled into your
+Android app. Then to use it, in places where you would have inflated
+`R.layouts.my_layout`, instead call `CompiledView.inflate`.
+
+Precompiling views like this generally improves the time needed to inflate them.
+
+This tool is still in its early stages and has a number of limitations.
+* Currently only one layout can be compiled at a time.
+* `merge` and `include` nodes are not supported.
+* View compilation is a manual process that requires code changes in the
+ application.
+* This only works for apps that do not use a custom layout inflater.
+* Other limitations yet to be discovered.
diff --git a/startop/tools/view_compiler/TEST_MAPPING b/startop/tools/view_compiler/TEST_MAPPING
new file mode 100644
index 0000000..cc4b17a
--- /dev/null
+++ b/startop/tools/view_compiler/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+ "presubmit": [
+ {
+ "name": "view-compiler-tests"
+ }
+ ]
+}
diff --git a/startop/tools/view_compiler/java_lang_builder.cc b/startop/tools/view_compiler/java_lang_builder.cc
new file mode 100644
index 0000000..0b8754f
--- /dev/null
+++ b/startop/tools/view_compiler/java_lang_builder.cc
@@ -0,0 +1,115 @@
+/*
+ * 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.
+ */
+
+#include "java_lang_builder.h"
+
+#include "android-base/stringprintf.h"
+
+using android::base::StringPrintf;
+using std::string;
+
+void JavaLangViewBuilder::Start() const {
+ out_ << StringPrintf("package %s;\n", package_.c_str())
+ << "import android.content.Context;\n"
+ "import android.content.res.Resources;\n"
+ "import android.content.res.XmlResourceParser;\n"
+ "import android.util.AttributeSet;\n"
+ "import android.util.Xml;\n"
+ "import android.view.*;\n"
+ "import android.widget.*;\n"
+ "\n"
+ "public final class CompiledView {\n"
+ "\n"
+ "static <T extends View> T createView(Context context, AttributeSet attrs, View parent, "
+ "String name, LayoutInflater.Factory factory, LayoutInflater.Factory2 factory2) {"
+ "\n"
+ " if (factory2 != null) {\n"
+ " return (T)factory2.onCreateView(parent, name, context, attrs);\n"
+ " } else if (factory != null) {\n"
+ " return (T)factory.onCreateView(name, context, attrs);\n"
+ " }\n"
+ // TODO: find a way to call the private factory
+ " return null;\n"
+ "}\n"
+ "\n"
+ " public static View inflate(Context context) {\n"
+ " try {\n"
+ " LayoutInflater inflater = LayoutInflater.from(context);\n"
+ " LayoutInflater.Factory factory = inflater.getFactory();\n"
+ " LayoutInflater.Factory2 factory2 = inflater.getFactory2();\n"
+ " Resources res = context.getResources();\n"
+ << StringPrintf(" XmlResourceParser xml = res.getLayout(%s.R.layout.%s);\n",
+ package_.c_str(),
+ layout_name_.c_str())
+ << " AttributeSet attrs = Xml.asAttributeSet(xml);\n"
+ // The Java-language XmlPullParser needs a call to next to find the start document tag.
+ " xml.next(); // start document\n";
+}
+
+void JavaLangViewBuilder::Finish() const {
+ out_ << " } catch (Exception e) {\n"
+ " return null;\n"
+ " }\n" // end try
+ " }\n" // end inflate
+ "}\n"; // end CompiledView
+}
+
+void JavaLangViewBuilder::StartView(const string& class_name) {
+ const string view_var = MakeVar("view");
+ const string layout_var = MakeVar("layout");
+ std::string parent = "null";
+ if (!view_stack_.empty()) {
+ const StackEntry& parent_entry = view_stack_.back();
+ parent = parent_entry.view_var;
+ }
+ out_ << " xml.next(); // <" << class_name << ">\n"
+ << StringPrintf(" %s %s = createView(context, attrs, %s, \"%s\", factory, factory2);\n",
+ class_name.c_str(),
+ view_var.c_str(),
+ parent.c_str(),
+ class_name.c_str())
+ << StringPrintf(" if (%s == null) %s = new %s(context, attrs);\n",
+ view_var.c_str(),
+ view_var.c_str(),
+ class_name.c_str());
+ if (!view_stack_.empty()) {
+ out_ << StringPrintf(" ViewGroup.LayoutParams %s = %s.generateLayoutParams(attrs);\n",
+ layout_var.c_str(),
+ parent.c_str());
+ }
+ view_stack_.push_back({class_name, view_var, layout_var});
+}
+
+void JavaLangViewBuilder::FinishView() {
+ const StackEntry var = view_stack_.back();
+ view_stack_.pop_back();
+ if (!view_stack_.empty()) {
+ const string& parent = view_stack_.back().view_var;
+ out_ << StringPrintf(" xml.next(); // </%s>\n", var.class_name.c_str())
+ << StringPrintf(" %s.addView(%s, %s);\n",
+ parent.c_str(),
+ var.view_var.c_str(),
+ var.layout_params_var.c_str());
+ } else {
+ out_ << StringPrintf(" return %s;\n", var.view_var.c_str());
+ }
+}
+
+const std::string JavaLangViewBuilder::MakeVar(std::string prefix) {
+ std::stringstream v;
+ v << prefix << view_id_++;
+ return v.str();
+}
diff --git a/startop/tools/view_compiler/java_lang_builder.h b/startop/tools/view_compiler/java_lang_builder.h
new file mode 100644
index 0000000..c8d20b2
--- /dev/null
+++ b/startop/tools/view_compiler/java_lang_builder.h
@@ -0,0 +1,65 @@
+/*
+ * 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 JAVA_LANG_BUILDER_H_
+#define JAVA_LANG_BUILDER_H_
+
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+// Build Java language code to instantiate views.
+//
+// This has a very small interface to make it easier to generate additional
+// backends, such as a direct-to-DEX version.
+class JavaLangViewBuilder {
+ public:
+ JavaLangViewBuilder(std::string package, std::string layout_name, std::ostream& out = std::cout)
+ : package_(package), layout_name_(layout_name), out_(out) {}
+
+ // Begin generating a class. Adds the package boilerplate, etc.
+ void Start() const;
+ // Finish generating a class, closing off any open curly braces, etc.
+ void Finish() const;
+
+ // Begin creating a view (i.e. process the opening tag)
+ void StartView(const std::string& class_name);
+ // Finish a view, after all of its child nodes have been processed.
+ void FinishView();
+
+ private:
+ const std::string MakeVar(std::string prefix);
+
+ std::string const package_;
+ std::string const layout_name_;
+
+ std::ostream& out_;
+
+ size_t view_id_ = 0;
+
+ struct StackEntry {
+ // The class name for this view object
+ const std::string class_name;
+
+ // The variable name that is holding the view object
+ const std::string view_var;
+
+ // The variable name that holds the object's layout parameters
+ const std::string layout_params_var;
+ };
+ std::vector<StackEntry> view_stack_;
+};
+
+#endif // JAVA_LANG_BUILDER_H_
diff --git a/startop/tools/view_compiler/main.cc b/startop/tools/view_compiler/main.cc
new file mode 100644
index 0000000..0ad7e24
--- /dev/null
+++ b/startop/tools/view_compiler/main.cc
@@ -0,0 +1,105 @@
+/*
+ * 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.
+ */
+
+#include "gflags/gflags.h"
+
+#include "java_lang_builder.h"
+#include "util.h"
+
+#include "tinyxml2.h"
+
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+using namespace tinyxml2;
+using std::string;
+
+constexpr char kStdoutFilename[]{"stdout"};
+
+DEFINE_string(package, "", "The package name for the generated class (required)");
+DEFINE_string(out, kStdoutFilename, "Where to write the generated class");
+
+namespace {
+class ViewCompilerXmlVisitor : public XMLVisitor {
+ public:
+ ViewCompilerXmlVisitor(JavaLangViewBuilder* builder) : builder_(builder) {}
+
+ bool VisitEnter(const XMLDocument& /*doc*/) override {
+ builder_->Start();
+ return true;
+ }
+
+ bool VisitExit(const XMLDocument& /*doc*/) override {
+ builder_->Finish();
+ return true;
+ }
+
+ bool VisitEnter(const XMLElement& element, const XMLAttribute* /*firstAttribute*/) override {
+ builder_->StartView(element.Name());
+ return true;
+ }
+
+ bool VisitExit(const XMLElement& /*element*/) override {
+ builder_->FinishView();
+ return true;
+ }
+
+ private:
+ JavaLangViewBuilder* builder_;
+};
+} // end namespace
+
+int main(int argc, char** argv) {
+ constexpr size_t kProgramName = 0;
+ constexpr size_t kFileNameParam = 1;
+ constexpr size_t kNumRequiredArgs = 2;
+
+ gflags::SetUsageMessage(
+ "Compile XML layout files into equivalent Java language code\n"
+ "\n"
+ " example usage: viewcompiler layout.xml --package com.example.androidapp");
+ gflags::ParseCommandLineFlags(&argc, &argv, /*remove_flags*/ true);
+
+ gflags::CommandLineFlagInfo cmd = gflags::GetCommandLineFlagInfoOrDie("package");
+ if (argc != kNumRequiredArgs || cmd.is_default) {
+ gflags::ShowUsageWithFlags(argv[kProgramName]);
+ return 1;
+ }
+
+ const char* const filename = argv[kFileNameParam];
+ const string layout_name = FindLayoutNameFromFilename(filename);
+
+ // We want to generate Java language code to inflate exactly this layout. This means
+ // generating code to walk the resource XML too.
+
+ XMLDocument xml;
+ xml.LoadFile(filename);
+
+ std::ofstream outfile;
+ if (FLAGS_out != kStdoutFilename) {
+ outfile.open(FLAGS_out);
+ }
+ JavaLangViewBuilder builder{
+ FLAGS_package, layout_name, FLAGS_out == kStdoutFilename ? std::cout : outfile};
+
+ ViewCompilerXmlVisitor visitor{&builder};
+ xml.Accept(&visitor);
+
+ return 0;
+}
\ No newline at end of file
diff --git a/startop/tools/view_compiler/util.cc b/startop/tools/view_compiler/util.cc
new file mode 100644
index 0000000..69df41d
--- /dev/null
+++ b/startop/tools/view_compiler/util.cc
@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+#include "util.h"
+
+using std::string;
+
+// TODO: see if we can borrow this from somewhere else, like aapt2.
+string FindLayoutNameFromFilename(const string& filename) {
+ size_t start = filename.rfind("/");
+ if (start == string::npos) {
+ start = 0;
+ } else {
+ start++; // advance past '/' character
+ }
+ size_t end = filename.find(".", start);
+
+ return filename.substr(start, end - start);
+}
diff --git a/startop/tools/view_compiler/util.h b/startop/tools/view_compiler/util.h
new file mode 100644
index 0000000..03e0939
--- /dev/null
+++ b/startop/tools/view_compiler/util.h
@@ -0,0 +1,23 @@
+/*
+ * 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 UTIL_H_
+#define UTIL_H_
+
+#include <string>
+
+std::string FindLayoutNameFromFilename(const std::string& filename);
+
+#endif // UTIL_H_
diff --git a/startop/tools/view_compiler/util_test.cc b/startop/tools/view_compiler/util_test.cc
new file mode 100644
index 0000000..d1540d3
--- /dev/null
+++ b/startop/tools/view_compiler/util_test.cc
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ */
+
+#include "util.h"
+
+#include "gtest/gtest.h"
+
+using std::string;
+
+TEST(UtilTest, FindLayoutNameFromFilename) {
+ EXPECT_EQ("bar", ::FindLayoutNameFromFilename("foo/bar.xml"));
+ EXPECT_EQ("bar", ::FindLayoutNameFromFilename("bar.xml"));
+ EXPECT_EQ("bar", ::FindLayoutNameFromFilename("./foo/bar.xml"));
+ EXPECT_EQ("bar", ::FindLayoutNameFromFilename("/foo/bar.xml"));
+}