tools/aapt2/compile/IdAssigner.cpp

/*
 * 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 "compile/IdAssigner.h"
#include "ResourceTable.h"
#include "process/IResourceTableConsumer.h"
#include "util/Util.h"

#include <cassert>
#include <map>

namespace aapt {

/**
 * Assigns the intended ID to the ResourceTablePackage, ResourceTableType, and
 * ResourceEntry,
 * as long as there is no existing ID or the ID is the same.
 */
static bool assignId(IDiagnostics* diag, const ResourceId& id,
                     const ResourceName& name, ResourceTablePackage* pkg,
                     ResourceTableType* type, ResourceEntry* entry) {
  if (pkg->id.value() == id.packageId()) {
    if (!type->id || type->id.value() == id.typeId()) {
      type->id = id.typeId();

      if (!entry->id || entry->id.value() == id.entryId()) {
        entry->id = id.entryId();
        return true;
      }
    }
  }

  const ResourceId existingId(pkg->id.value(), type->id ? type->id.value() : 0,
                              entry->id ? entry->id.value() : 0);
  diag->error(DiagMessage() << "can't assign ID " << id << " to resource "
                            << name << " with conflicting ID " << existingId);
  return false;
}

bool IdAssigner::consume(IAaptContext* context, ResourceTable* table) {
  std::map<ResourceId, ResourceName> assignedIds;

  for (auto& package : table->packages) {
    assert(package->id && "packages must have manually assigned IDs");

    for (auto& type : package->types) {
      for (auto& entry : type->entries) {
        const ResourceName name(package->name, type->type, entry->name);

        if (mAssignedIdMap) {
          // Assign the pre-assigned stable ID meant for this resource.
          const auto iter = mAssignedIdMap->find(name);
          if (iter != mAssignedIdMap->end()) {
            const ResourceId assignedId = iter->second;
            const bool result =
                assignId(context->getDiagnostics(), assignedId, name,
                         package.get(), type.get(), entry.get());
            if (!result) {
              return false;
            }
          }
        }

        if (package->id && type->id && entry->id) {
          // If the ID is set for this resource, then reserve it.
          ResourceId resourceId(package->id.value(), type->id.value(),
                                entry->id.value());
          auto result = assignedIds.insert({resourceId, name});
          const ResourceName& existingName = result.first->second;
          if (!result.second) {
            context->getDiagnostics()->error(
                DiagMessage() << "resource " << name << " has same ID "
                              << resourceId << " as " << existingName);
            return false;
          }
        }
      }
    }
  }

  if (mAssignedIdMap) {
    // Reserve all the IDs mentioned in the stable ID map. That way we won't
    // assign
    // IDs that were listed in the map if they don't exist in the table.
    for (const auto& stableIdEntry : *mAssignedIdMap) {
      const ResourceName& preAssignedName = stableIdEntry.first;
      const ResourceId& preAssignedId = stableIdEntry.second;
      auto result = assignedIds.insert({preAssignedId, preAssignedName});
      const ResourceName& existingName = result.first->second;
      if (!result.second && existingName != preAssignedName) {
        context->getDiagnostics()->error(
            DiagMessage() << "stable ID " << preAssignedId << " for resource "
                          << preAssignedName << " is already taken by resource "
                          << existingName);
        return false;
      }
    }
  }

  // Assign any resources without IDs the next available ID. Gaps will be filled
  // if possible,
  // unless those IDs have been reserved.

  const auto assignedIdsIterEnd = assignedIds.end();
  for (auto& package : table->packages) {
    assert(package->id && "packages must have manually assigned IDs");

    // Build a half filled ResourceId object, which will be used to find the
    // closest matching
    // reserved ID in the assignedId map. From that point the next available
    // type ID can be
    // found.
    ResourceId resourceId(package->id.value(), 0, 0);
    uint8_t nextExpectedTypeId = 1;

    // Find the closest matching ResourceId that is <= the one with only the
    // package set.
    auto nextTypeIter = assignedIds.lower_bound(resourceId);
    for (auto& type : package->types) {
      if (!type->id) {
        // We need to assign a type ID. Iterate over the reserved IDs until we
        // find
        // some type ID that is a distance of 2 greater than the last one we've
        // seen.
        // That means there is an available type ID between these reserved IDs.
        while (nextTypeIter != assignedIdsIterEnd) {
          if (nextTypeIter->first.packageId() != package->id.value()) {
            break;
          }

          const uint8_t typeId = nextTypeIter->first.typeId();
          if (typeId > nextExpectedTypeId) {
            // There is a gap in the type IDs, so use the missing one.
            type->id = nextExpectedTypeId++;
            break;
          }

          // Set our expectation to be the next type ID after the reserved one
          // we
          // just saw.
          nextExpectedTypeId = typeId + 1;

          // Move to the next reserved ID.
          ++nextTypeIter;
        }

        if (!type->id) {
          // We must have hit the end of the reserved IDs and not found a gap.
          // That means the next ID is available.
          type->id = nextExpectedTypeId++;
        }
      }

      resourceId = ResourceId(package->id.value(), type->id.value(), 0);
      uint16_t nextExpectedEntryId = 0;

      // Find the closest matching ResourceId that is <= the one with only the
      // package
      // and type set.
      auto nextEntryIter = assignedIds.lower_bound(resourceId);
      for (auto& entry : type->entries) {
        if (!entry->id) {
          // We need to assign an entry ID. Iterate over the reserved IDs until
          // we find
          // some entry ID that is a distance of 2 greater than the last one
          // we've seen.
          // That means there is an available entry ID between these reserved
          // IDs.
          while (nextEntryIter != assignedIdsIterEnd) {
            if (nextEntryIter->first.packageId() != package->id.value() ||
                nextEntryIter->first.typeId() != type->id.value()) {
              break;
            }

            const uint16_t entryId = nextEntryIter->first.entryId();
            if (entryId > nextExpectedEntryId) {
              // There is a gap in the entry IDs, so use the missing one.
              entry->id = nextExpectedEntryId++;
              break;
            }

            // Set our expectation to be the next type ID after the reserved one
            // we
            // just saw.
            nextExpectedEntryId = entryId + 1;

            // Move to the next reserved entry ID.
            ++nextEntryIter;
          }

          if (!entry->id) {
            // We must have hit the end of the reserved IDs and not found a gap.
            // That means the next ID is available.
            entry->id = nextExpectedEntryId++;
          }
        }
      }
    }
  }
  return true;
}

}  // namespace aapt