AAPT2: Fix overlay support

Supports the <add-resource> tag and mimics old AAPT behavior of
not allowing new resources defined unless <add-resource> was used
or --auto-add-overlay was specified.

Change-Id: I9b461137357617ade37fd7045b418b8e6450b9c4
diff --git a/tools/aapt2/io/ZipArchive.cpp b/tools/aapt2/io/ZipArchive.cpp
new file mode 100644
index 0000000..bf0f4aa
--- /dev/null
+++ b/tools/aapt2/io/ZipArchive.cpp
@@ -0,0 +1,135 @@
+/*
+ * 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 "Source.h"
+#include "io/ZipArchive.h"
+#include "util/Util.h"
+
+#include <utils/FileMap.h>
+#include <ziparchive/zip_archive.h>
+
+namespace aapt {
+namespace io {
+
+ZipFile::ZipFile(ZipArchiveHandle handle, const ZipEntry& entry, const Source& source) :
+        mZipHandle(handle), mZipEntry(entry), mSource(source) {
+}
+
+std::unique_ptr<IData> ZipFile::openAsData() {
+    if (mZipEntry.method == kCompressStored) {
+        int fd = GetFileDescriptor(mZipHandle);
+
+        android::FileMap fileMap;
+        bool result = fileMap.create(nullptr, fd, mZipEntry.offset,
+                                     mZipEntry.uncompressed_length, true);
+        if (!result) {
+            return {};
+        }
+        return util::make_unique<MmappedData>(std::move(fileMap));
+
+    } else {
+        std::unique_ptr<uint8_t[]> data = std::unique_ptr<uint8_t[]>(
+                new uint8_t[mZipEntry.uncompressed_length]);
+        int32_t result = ExtractToMemory(mZipHandle, &mZipEntry, data.get(),
+                                         static_cast<uint32_t>(mZipEntry.uncompressed_length));
+        if (result != 0) {
+            return {};
+        }
+        return util::make_unique<MallocData>(std::move(data), mZipEntry.uncompressed_length);
+    }
+}
+
+const Source& ZipFile::getSource() const {
+    return mSource;
+}
+
+ZipFileCollectionIterator::ZipFileCollectionIterator(ZipFileCollection* collection) :
+        mCurrent(collection->mFiles.begin()), mEnd(collection->mFiles.end()) {
+}
+
+bool ZipFileCollectionIterator::hasNext() {
+    return mCurrent != mEnd;
+}
+
+IFile* ZipFileCollectionIterator::next() {
+    IFile* result = mCurrent->second.get();
+    ++mCurrent;
+    return result;
+}
+
+ZipFileCollection::ZipFileCollection() : mHandle(nullptr) {
+}
+
+std::unique_ptr<ZipFileCollection> ZipFileCollection::create(const StringPiece& path,
+                                                             std::string* outError) {
+    std::unique_ptr<ZipFileCollection> collection = std::unique_ptr<ZipFileCollection>(
+            new ZipFileCollection());
+
+    int32_t result = OpenArchive(path.data(), &collection->mHandle);
+    if (result != 0) {
+        if (outError) *outError = ErrorCodeString(result);
+        return {};
+    }
+
+    ZipString suffix(".flat");
+    void* cookie = nullptr;
+    result = StartIteration(collection->mHandle, &cookie, nullptr, &suffix);
+    if (result != 0) {
+        if (outError) *outError = ErrorCodeString(result);
+        return {};
+    }
+
+    using IterationEnder = std::unique_ptr<void, decltype(EndIteration)*>;
+    IterationEnder iterationEnder(cookie, EndIteration);
+
+    ZipString zipEntryName;
+    ZipEntry zipData;
+    while ((result = Next(cookie, &zipData, &zipEntryName)) == 0) {
+        std::string zipEntryPath = std::string(reinterpret_cast<const char*>(zipEntryName.name),
+                                               zipEntryName.name_length);
+        std::string nestedPath = path.toString() + "@" + zipEntryPath;
+        collection->mFiles[zipEntryPath] = util::make_unique<ZipFile>(collection->mHandle,
+                                                                      zipData,
+                                                                      Source(nestedPath));
+    }
+
+    if (result != -1) {
+        if (outError) *outError = ErrorCodeString(result);
+        return {};
+    }
+    return collection;
+}
+
+IFile* ZipFileCollection::findFile(const StringPiece& path) {
+    auto iter = mFiles.find(path.toString());
+    if (iter != mFiles.end()) {
+        return iter->second.get();
+    }
+    return nullptr;
+}
+
+std::unique_ptr<IFileCollectionIterator> ZipFileCollection::iterator() {
+    return util::make_unique<ZipFileCollectionIterator>(this);
+}
+
+ZipFileCollection::~ZipFileCollection() {
+    if (mHandle) {
+        CloseArchive(mHandle);
+    }
+}
+
+} // namespace io
+} // namespace aapt