tools/aapt2/ResourceTable.h

/*
 * 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.
 */

#ifndef AAPT_RESOURCE_TABLE_H
#define AAPT_RESOURCE_TABLE_H

#include "Diagnostics.h"
#include "Resource.h"
#include "ResourceValues.h"
#include "Source.h"
#include "StringPool.h"
#include "io/File.h"

#include "android-base/macros.h"
#include "androidfw/ConfigDescription.h"
#include "androidfw/StringPiece.h"

#include <functional>
#include <map>
#include <memory>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using PolicyFlags = android::ResTable_overlayable_policy_header::PolicyFlags;

namespace aapt {

// The Public status of a resource.
struct Visibility {
  enum class Level {
    kUndefined,
    kPrivate,
    kPublic,
  };

  Level level = Level::kUndefined;
  Source source;
  std::string comment;
};

// Represents <add-resource> in an overlay.
struct AllowNew {
  Source source;
  std::string comment;
};

struct Overlayable {
  Overlayable() = default;
   Overlayable(const android::StringPiece& name, const android::StringPiece& actor)
       : name(name.to_string()), actor(actor.to_string()) {}
   Overlayable(const android::StringPiece& name, const android::StringPiece& actor,
                    const Source& source)
       : name(name.to_string()), actor(actor.to_string()), source(source ){}

  static const char* kActorScheme;
  std::string name;
  std::string actor;
  Source source;
};

// Represents a declaration that a resource is overlayable at runtime.
struct OverlayableItem {
  explicit OverlayableItem(const std::shared_ptr<Overlayable>& overlayable)
      : overlayable(overlayable) {}
  std::shared_ptr<Overlayable> overlayable;
  PolicyFlags policies = PolicyFlags::NONE;
  std::string comment;
  Source source;
};

class ResourceConfigValue {
 public:
  // The configuration for which this value is defined.
  const android::ConfigDescription config;

  // The product for which this value is defined.
  const std::string product;

  // The actual Value.
  std::unique_ptr<Value> value;

  ResourceConfigValue(const android::ConfigDescription& config, const android::StringPiece& product)
      : config(config), product(product.to_string()) {}

 private:
  DISALLOW_COPY_AND_ASSIGN(ResourceConfigValue);
};

// Represents a resource entry, which may have varying values for each defined configuration.
class ResourceEntry {
 public:
  // The name of the resource. Immutable, as this determines the order of this resource
  // when doing lookups.
  const std::string name;

  // The entry ID for this resource (the EEEE in 0xPPTTEEEE).
  Maybe<uint16_t> id;

  // Whether this resource is public (and must maintain the same entry ID across builds).
  Visibility visibility;

  Maybe<AllowNew> allow_new;

  // The declarations of this resource as overlayable for RROs
  Maybe<OverlayableItem> overlayable_item;

  // The resource's values for each configuration.
  std::vector<std::unique_ptr<ResourceConfigValue>> values;

  explicit ResourceEntry(const android::StringPiece& name) : name(name.to_string()) {}

  ResourceConfigValue* FindValue(const android::ConfigDescription& config);

  ResourceConfigValue* FindValue(const android::ConfigDescription& config,
                                 const android::StringPiece& product);

  ResourceConfigValue* FindOrCreateValue(const android::ConfigDescription& config,
                                         const android::StringPiece& product);
  std::vector<ResourceConfigValue*> FindAllValues(const android::ConfigDescription& config);

  template <typename Func>
  std::vector<ResourceConfigValue*> FindValuesIf(Func f) {
    std::vector<ResourceConfigValue*> results;
    for (auto& config_value : values) {
      if (f(config_value.get())) {
        results.push_back(config_value.get());
      }
    }
    return results;
  }

  bool HasDefaultValue() const;

 private:
  DISALLOW_COPY_AND_ASSIGN(ResourceEntry);
};

// Represents a resource type (eg. string, drawable, layout, etc.) containing resource entries.
class ResourceTableType {
 public:
  // The logical type of resource (string, drawable, layout, etc.).
  const ResourceType type;

  // The type ID for this resource (the TT in 0xPPTTEEEE).
  Maybe<uint8_t> id;

  // Whether this type is public (and must maintain the same type ID across builds).
  Visibility::Level visibility_level = Visibility::Level::kUndefined;

  // List of resources for this type.
  std::vector<std::unique_ptr<ResourceEntry>> entries;

  explicit ResourceTableType(const ResourceType type) : type(type) {}

  ResourceEntry* FindEntry(const android::StringPiece& name,
                           Maybe<uint16_t> id = Maybe<uint16_t>());
  ResourceEntry* FindOrCreateEntry(const android::StringPiece& name,
                                   Maybe<uint16_t> id = Maybe<uint16_t>());

 private:
  DISALLOW_COPY_AND_ASSIGN(ResourceTableType);
};

class ResourceTablePackage {
 public:
  std::string name;

  // The package ID (the PP in 0xPPTTEEEE).
  Maybe<uint8_t> id;

  std::vector<std::unique_ptr<ResourceTableType>> types;

  ResourceTablePackage() = default;
  ResourceTableType* FindType(ResourceType type, Maybe<uint8_t> id = Maybe<uint8_t>());
  ResourceTableType* FindOrCreateType(const ResourceType type,
                                      Maybe<uint8_t> id = Maybe<uint8_t>());

 private:
  DISALLOW_COPY_AND_ASSIGN(ResourceTablePackage);
};

// The container and index for all resources defined for an app.
class ResourceTable {
 public:
  ResourceTable() = default;
  explicit ResourceTable(bool validate_resources) : validate_resources_(validate_resources) {}

  enum class CollisionResult { kKeepBoth, kKeepOriginal, kConflict, kTakeNew };

  using CollisionResolverFunc = std::function<CollisionResult(Value*, Value*)>;

  // When a collision of resources occurs, this method decides which value to keep.
  static CollisionResult ResolveValueCollision(Value* existing, Value* incoming);

  // When a collision of resources occurs, this method keeps both values
  static CollisionResult IgnoreCollision(Value* existing, Value* incoming);

  bool AddResource(const ResourceNameRef& name, const android::ConfigDescription& config,
                   const android::StringPiece& product, std::unique_ptr<Value> value,
                   IDiagnostics* diag);

  bool AddResourceWithId(const ResourceNameRef& name, const ResourceId& res_id,
                         const android::ConfigDescription& config,
                         const android::StringPiece& product, std::unique_ptr<Value> value,
                         IDiagnostics* diag);

  // Same as AddResource, but doesn't verify the validity of the name. This is used
  // when loading resources from an existing binary resource table that may have mangled names.
  bool AddResourceMangled(const ResourceNameRef& name, const android::ConfigDescription& config,
                          const android::StringPiece& product, std::unique_ptr<Value> value,
                          IDiagnostics* diag);

  bool AddResourceWithIdMangled(const ResourceNameRef& name, const ResourceId& id,
                                const android::ConfigDescription& config,
                                const android::StringPiece& product, std::unique_ptr<Value> value,
                                IDiagnostics* diag);

  bool GetValidateResources();

  bool SetVisibility(const ResourceNameRef& name, const Visibility& visibility, IDiagnostics* diag);
  bool SetVisibilityWithId(const ResourceNameRef& name, const Visibility& visibility,
                           const ResourceId& res_id, IDiagnostics* diag);
  bool SetVisibilityWithIdMangled(const ResourceNameRef& name, const Visibility& visibility,
                                  const ResourceId& res_id, IDiagnostics* diag);

  bool SetOverlayable(const ResourceNameRef& name, const OverlayableItem& overlayable,
                      IDiagnostics *diag);

  bool SetAllowNew(const ResourceNameRef& name, const AllowNew& allow_new, IDiagnostics* diag);
  bool SetAllowNewMangled(const ResourceNameRef& name, const AllowNew& allow_new,
                          IDiagnostics* diag);

  struct SearchResult {
    ResourceTablePackage* package;
    ResourceTableType* type;
    ResourceEntry* entry;
  };

  Maybe<SearchResult> FindResource(const ResourceNameRef& name) const;

  // Returns the package struct with the given name, or nullptr if such a package does not
  // exist. The empty string is a valid package and typically is used to represent the
  // 'current' package before it is known to the ResourceTable.
  ResourceTablePackage* FindPackage(const android::StringPiece& name) const;

  ResourceTablePackage* FindPackageById(uint8_t id) const;

  ResourceTablePackage* CreatePackage(const android::StringPiece& name, Maybe<uint8_t> id = {});

  // Attempts to find a package having the specified name and ID. If not found, a new package
  // of the specified parameters is created and returned.
  ResourceTablePackage* CreatePackageAllowingDuplicateNames(const android::StringPiece& name,
                                                            const Maybe<uint8_t> id);

  std::unique_ptr<ResourceTable> Clone() const;

  // The string pool used by this resource table. Values that reference strings must use
  // this pool to create their strings.
  // NOTE: `string_pool` must come before `packages` so that it is destroyed after.
  // When `string_pool` references are destroyed (as they will be when `packages` is destroyed),
  // they decrement a refCount, which would cause invalid memory access if the pool was already
  // destroyed.
  StringPool string_pool;

  // The list of packages in this table, sorted alphabetically by package name and increasing
  // package ID (missing ID being the lowest).
  std::vector<std::unique_ptr<ResourceTablePackage>> packages;

  // Set of dynamic packages that this table may reference. Their package names get encoded
  // into the resources.arsc along with their compile-time assigned IDs.
  std::map<size_t, std::string> included_packages_;

 private:
  // The function type that validates a symbol name. Returns a non-empty StringPiece representing
  // the offending character (which may be more than one byte in UTF-8). Returns an empty string
  // if the name was valid.
  using NameValidator = android::StringPiece(const android::StringPiece&);

  ResourceTablePackage* FindOrCreatePackage(const android::StringPiece& name);

  bool ValidateName(NameValidator validator, const ResourceNameRef& name, const Source& source,
                    IDiagnostics* diag);

  bool AddResourceImpl(const ResourceNameRef& name, const ResourceId& res_id,
                       const android::ConfigDescription& config,
                       const android::StringPiece& product, std::unique_ptr<Value> value,
                       NameValidator name_validator, const CollisionResolverFunc& conflict_resolver,
                       IDiagnostics* diag);

  bool SetVisibilityImpl(const ResourceNameRef& name, const Visibility& visibility,
                         const ResourceId& res_id, NameValidator name_validator,
                         IDiagnostics* diag);

  bool SetAllowNewImpl(const ResourceNameRef& name, const AllowNew& allow_new,
                       NameValidator name_validator, IDiagnostics* diag);

  bool SetOverlayableImpl(const ResourceNameRef &name, const OverlayableItem& overlayable,
                          NameValidator name_validator, IDiagnostics *diag);

  // Controls whether the table validates resource names and prevents duplicate resource names
  bool validate_resources_ = true;

  DISALLOW_COPY_AND_ASSIGN(ResourceTable);
};

}  // namespace aapt

#endif  // AAPT_RESOURCE_TABLE_H