AAPT2: Support generating Manifest.java

This includes comments from AndroidManifest.xml.

Change-Id: I412d9ecb12bad20a49a683d6b3bea4a0be1235ae
diff --git a/tools/aapt2/java/JavaClassGenerator.cpp b/tools/aapt2/java/JavaClassGenerator.cpp
new file mode 100644
index 0000000..0175489
--- /dev/null
+++ b/tools/aapt2/java/JavaClassGenerator.cpp
@@ -0,0 +1,229 @@
+/*
+ * Copyright (C) 2015 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 "NameMangler.h"
+#include "Resource.h"
+#include "ResourceTable.h"
+#include "ResourceValues.h"
+#include "java/AnnotationProcessor.h"
+#include "java/JavaClassGenerator.h"
+#include "util/StringPiece.h"
+
+#include <algorithm>
+#include <ostream>
+#include <set>
+#include <sstream>
+#include <tuple>
+
+namespace aapt {
+
+// The number of attributes to emit per line in a Styleable array.
+constexpr size_t kAttribsPerLine = 4;
+
+JavaClassGenerator::JavaClassGenerator(ResourceTable* table, JavaClassGeneratorOptions options) :
+        mTable(table), mOptions(options) {
+}
+
+static void generateHeader(const StringPiece16& packageNameToGenerate, std::ostream* out) {
+    *out << "/* AUTO-GENERATED FILE. DO NOT MODIFY.\n"
+            " *\n"
+            " * This class was automatically generated by the\n"
+            " * aapt tool from the resource data it found. It\n"
+            " * should not be modified by hand.\n"
+            " */\n\n"
+            "package " << packageNameToGenerate << ";\n\n";
+}
+
+static const std::set<StringPiece16> sJavaIdentifiers = {
+    u"abstract", u"assert", u"boolean", u"break", u"byte",
+    u"case", u"catch", u"char", u"class", u"const", u"continue",
+    u"default", u"do", u"double", u"else", u"enum", u"extends",
+    u"final", u"finally", u"float", u"for", u"goto", u"if",
+    u"implements", u"import", u"instanceof", u"int", u"interface",
+    u"long", u"native", u"new", u"package", u"private", u"protected",
+    u"public", u"return", u"short", u"static", u"strictfp", u"super",
+    u"switch", u"synchronized", u"this", u"throw", u"throws",
+    u"transient", u"try", u"void", u"volatile", u"while", u"true",
+    u"false", u"null"
+};
+
+static bool isValidSymbol(const StringPiece16& symbol) {
+    return sJavaIdentifiers.find(symbol) == sJavaIdentifiers.end();
+}
+
+/*
+ * Java symbols can not contain . or -, but those are valid in a resource name.
+ * Replace those with '_'.
+ */
+static std::u16string transform(const StringPiece16& symbol) {
+    std::u16string output = symbol.toString();
+    for (char16_t& c : output) {
+        if (c == u'.' || c == u'-') {
+            c = u'_';
+        }
+    }
+    return output;
+}
+
+bool JavaClassGenerator::skipSymbol(SymbolState state) {
+    switch (mOptions.types) {
+    case JavaClassGeneratorOptions::SymbolTypes::kAll:
+        return false;
+    case JavaClassGeneratorOptions::SymbolTypes::kPublicPrivate:
+        return state == SymbolState::kUndefined;
+    case JavaClassGeneratorOptions::SymbolTypes::kPublic:
+        return state != SymbolState::kPublic;
+    }
+    return true;
+}
+
+void JavaClassGenerator::generateStyleable(const StringPiece16& packageNameToGenerate,
+                                           const std::u16string& entryName,
+                                           const Styleable* styleable,
+                                           std::ostream* out) {
+    const StringPiece finalModifier = mOptions.useFinal ? " final" : "";
+
+    // This must be sorted by resource ID.
+    std::vector<std::pair<ResourceId, ResourceNameRef>> sortedAttributes;
+    sortedAttributes.reserve(styleable->entries.size());
+    for (const auto& attr : styleable->entries) {
+        // If we are not encoding final attributes, the styleable entry may have no ID
+        // if we are building a static library.
+        assert((!mOptions.useFinal || attr.id) && "no ID set for Styleable entry");
+        assert(attr.name && "no name set for Styleable entry");
+        sortedAttributes.emplace_back(attr.id ? attr.id.value() : ResourceId(0), attr.name.value());
+    }
+    std::sort(sortedAttributes.begin(), sortedAttributes.end());
+
+    // First we emit the array containing the IDs of each attribute.
+    *out << "        "
+         << "public static final int[] " << transform(entryName) << " = {";
+
+    const size_t attrCount = sortedAttributes.size();
+    for (size_t i = 0; i < attrCount; i++) {
+        if (i % kAttribsPerLine == 0) {
+            *out << "\n            ";
+        }
+
+        *out << sortedAttributes[i].first;
+        if (i != attrCount - 1) {
+            *out << ", ";
+        }
+    }
+    *out << "\n        };\n";
+
+    // Now we emit the indices into the array.
+    for (size_t i = 0; i < attrCount; i++) {
+        *out << "        "
+             << "public static" << finalModifier
+             << " int " << transform(entryName);
+
+        // We may reference IDs from other packages, so prefix the entry name with
+        // the package.
+        const ResourceNameRef& itemName = sortedAttributes[i].second;
+        if (!itemName.package.empty() && packageNameToGenerate != itemName.package) {
+            *out << "_" << transform(itemName.package);
+        }
+        *out << "_" << transform(itemName.entry) << " = " << i << ";\n";
+    }
+}
+
+bool JavaClassGenerator::generateType(const StringPiece16& packageNameToGenerate,
+                                      const ResourceTablePackage* package,
+                                      const ResourceTableType* type,
+                                      std::ostream* out) {
+    const StringPiece finalModifier = mOptions.useFinal ? " final" : "";
+
+    std::u16string unmangledPackage;
+    std::u16string unmangledName;
+    for (const auto& entry : type->entries) {
+        if (skipSymbol(entry->symbolStatus.state)) {
+            continue;
+        }
+
+        ResourceId id(package->id.value(), type->id.value(), entry->id.value());
+        assert(id.isValid());
+
+        unmangledName = entry->name;
+        if (NameMangler::unmangle(&unmangledName, &unmangledPackage)) {
+            // The entry name was mangled, and we successfully unmangled it.
+            // Check that we want to emit this symbol.
+            if (package->name != unmangledPackage) {
+                // Skip the entry if it doesn't belong to the package we're writing.
+                continue;
+            }
+        } else {
+            if (packageNameToGenerate != package->name) {
+                // We are processing a mangled package name,
+                // but this is a non-mangled resource.
+                continue;
+            }
+        }
+
+        if (!isValidSymbol(unmangledName)) {
+            ResourceNameRef resourceName(packageNameToGenerate, type->type, unmangledName);
+            std::stringstream err;
+            err << "invalid symbol name '" << resourceName << "'";
+            mError = err.str();
+            return false;
+        }
+
+        if (type->type == ResourceType::kStyleable) {
+            assert(!entry->values.empty());
+            generateStyleable(packageNameToGenerate, unmangledName, static_cast<const Styleable*>(
+                    entry->values.front().value.get()), out);
+        } else {
+            *out << "        " << "public static" << finalModifier
+                 << " int " << transform(unmangledName) << " = " << id << ";\n";
+        }
+    }
+    return true;
+}
+
+bool JavaClassGenerator::generate(const StringPiece16& packageNameToGenerate, std::ostream* out) {
+    return generate(packageNameToGenerate, packageNameToGenerate, out);
+}
+
+bool JavaClassGenerator::generate(const StringPiece16& packageNameToGenerate,
+                                  const StringPiece16& outPackageName, std::ostream* out) {
+    generateHeader(outPackageName, out);
+
+    *out << "public final class R {\n";
+
+    for (const auto& package : mTable->packages) {
+        for (const auto& type : package->types) {
+            StringPiece16 typeStr;
+            if (type->type == ResourceType::kAttrPrivate) {
+                typeStr = toString(ResourceType::kAttr);
+            } else {
+                typeStr = toString(type->type);
+            }
+            *out << "    public static final class " << typeStr << " {\n";
+            if (!generateType(packageNameToGenerate, package.get(), type.get(), out)) {
+                return false;
+            }
+            *out << "    }\n";
+        }
+    }
+
+    *out << "}\n";
+    out->flush();
+    return true;
+}
+
+
+
+} // namespace aapt