AAPT2: Separate out the various steps

An early refactor. Some ideas became clearer as
development continued. Now the various phases are much
clearer and more easily reusable.

Also added a ton of tests!

Change-Id: Ic8f0a70c8222370352e63533b329c40457c0903e
diff --git a/tools/aapt2/link/TableMerger.cpp b/tools/aapt2/link/TableMerger.cpp
new file mode 100644
index 0000000..d5fd1fc
--- /dev/null
+++ b/tools/aapt2/link/TableMerger.cpp
@@ -0,0 +1,183 @@
+/*
+ * 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 "ResourceTable.h"
+#include "ResourceValues.h"
+#include "ValueVisitor.h"
+
+#include "link/TableMerger.h"
+#include "util/Util.h"
+
+#include <cassert>
+
+namespace aapt {
+
+TableMerger::TableMerger(IAaptContext* context, ResourceTable* outTable) :
+        mContext(context), mMasterTable(outTable) {
+    // Create the desired package that all tables will be merged into.
+    mMasterPackage = mMasterTable->createPackage(
+            mContext->getCompilationPackage(), mContext->getPackageId());
+    assert(mMasterPackage && "package name or ID already taken");
+}
+
+bool TableMerger::merge(const Source& src, ResourceTable* table) {
+    const uint8_t desiredPackageId = mContext->getPackageId();
+
+    bool error = false;
+    for (auto& package : table->packages) {
+        // Warn of packages with an unrelated ID.
+        if (package->id && package->id.value() != desiredPackageId) {
+            mContext->getDiagnostics()->warn(DiagMessage(src)
+                                             << "ignoring package " << package->name);
+            continue;
+        }
+
+        bool manglePackage = false;
+        if (!package->name.empty() && mContext->getCompilationPackage() != package->name) {
+            manglePackage = true;
+            mMergedPackages.insert(package->name);
+        }
+
+        // Merge here. Once the entries are merged and mangled, any references to
+        // them are still valid. This is because un-mangled references are
+        // mangled, then looked up at resolution time.
+        // Also, when linking, we convert references with no package name to use
+        // the compilation package name.
+        if (!doMerge(src, table, package.get(), manglePackage)) {
+            error = true;
+        }
+    }
+    return !error;
+}
+
+bool TableMerger::doMerge(const Source& src, ResourceTable* srcTable,
+                          ResourceTablePackage* srcPackage, const bool manglePackage) {
+    bool error = false;
+
+    for (auto& srcType : srcPackage->types) {
+        ResourceTableType* dstType = mMasterPackage->findOrCreateType(srcType->type);
+        if (srcType->publicStatus.isPublic) {
+            if (dstType->publicStatus.isPublic && dstType->id && srcType->id
+                    && dstType->id.value() == srcType->id.value()) {
+                // Both types are public and have different IDs.
+                mContext->getDiagnostics()->error(DiagMessage(src)
+                                                  << "can not merge type '"
+                                                  << srcType->type
+                                                  << "': conflicting public IDs");
+                error = true;
+                continue;
+            }
+
+            dstType->publicStatus = std::move(srcType->publicStatus);
+            dstType->id = srcType->id;
+        }
+
+        for (auto& srcEntry : srcType->entries) {
+            ResourceEntry* dstEntry;
+            if (manglePackage) {
+                dstEntry = dstType->findOrCreateEntry(NameMangler::mangleEntry(
+                        srcPackage->name, srcEntry->name));
+            } else {
+                dstEntry = dstType->findOrCreateEntry(srcEntry->name);
+            }
+
+            if (srcEntry->publicStatus.isPublic) {
+                if (dstEntry->publicStatus.isPublic && dstEntry->id && srcEntry->id
+                        && dstEntry->id.value() != srcEntry->id.value()) {
+                    // Both entries are public and have different IDs.
+                    mContext->getDiagnostics()->error(DiagMessage(src)
+                                                      << "can not merge entry '"
+                                                      << srcEntry->name
+                                                      << "': conflicting public IDs");
+                    error = true;
+                    continue;
+                }
+
+                dstEntry->publicStatus = std::move(srcEntry->publicStatus);
+                dstEntry->id = srcEntry->id;
+            }
+
+            for (ResourceConfigValue& srcValue : srcEntry->values) {
+                auto cmp = [](const ResourceConfigValue& a,
+                              const ConfigDescription& b) -> bool {
+                    return a.config < b;
+                };
+
+                auto iter = std::lower_bound(dstEntry->values.begin(), dstEntry->values.end(),
+                                             srcValue.config, cmp);
+
+                if (iter != dstEntry->values.end() && iter->config == srcValue.config) {
+                    const int collisionResult = ResourceTable::resolveValueCollision(
+                            iter->value.get(), srcValue.value.get());
+                    if (collisionResult == 0) {
+                        // Error!
+                        ResourceNameRef resourceName =
+                                { srcPackage->name, srcType->type, srcEntry->name };
+                        mContext->getDiagnostics()->error(DiagMessage(srcValue.source)
+                                                          << "resource '" << resourceName
+                                                          << "' has a conflicting value for "
+                                                          << "configuration ("
+                                                          << srcValue.config << ")");
+                        mContext->getDiagnostics()->note(DiagMessage(iter->source)
+                                                         << "originally defined here");
+                        error = true;
+                        continue;
+                    } else if (collisionResult < 0) {
+                        // Keep our existing value.
+                        continue;
+                    }
+
+                } else {
+                    // Insert a new value.
+                    iter = dstEntry->values.insert(iter,
+                                                   ResourceConfigValue{ srcValue.config });
+                }
+
+                iter->source = std::move(srcValue.source);
+                iter->comment = std::move(srcValue.comment);
+                if (manglePackage) {
+                    iter->value = cloneAndMangle(srcTable, srcPackage->name,
+                                                 srcValue.value.get());
+                } else {
+                    iter->value = clone(srcValue.value.get());
+                }
+            }
+        }
+    }
+    return !error;
+}
+
+std::unique_ptr<Value> TableMerger::cloneAndMangle(ResourceTable* table,
+                                                   const std::u16string& package,
+                                                   Value* value) {
+    if (FileReference* f = valueCast<FileReference>(value)) {
+        // Mangle the path.
+        StringPiece16 prefix, entry, suffix;
+        if (util::extractResFilePathParts(*f->path, &prefix, &entry, &suffix)) {
+            std::u16string mangledEntry = NameMangler::mangleEntry(package, entry.toString());
+            std::u16string newPath = prefix.toString() + mangledEntry + suffix.toString();
+            mFilesToMerge.push(FileToMerge{ table, *f->path, newPath });
+            return util::make_unique<FileReference>(mMasterTable->stringPool.makeRef(newPath));
+        }
+    }
+    return clone(value);
+}
+
+std::unique_ptr<Value> TableMerger::clone(Value* value) {
+    return std::unique_ptr<Value>(value->clone(&mMasterTable->stringPool));
+}
+
+} // namespace aapt