gecko-dev/dom/plugins/ipc/PluginScriptableObjectChild.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=2 et :
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef dom_plugins_PluginScriptableObjectChild_h
#define dom_plugins_PluginScriptableObjectChild_h 1

#include "mozilla/plugins/PPluginScriptableObjectChild.h"
#include "mozilla/plugins/PluginMessageUtils.h"
#include "mozilla/plugins/PluginTypes.h"

#include "npruntime.h"
#include "nsDataHashtable.h"

namespace mozilla {
namespace plugins {

class PluginInstanceChild;
class PluginScriptableObjectChild;

struct ChildNPObject : NPObject {
  ChildNPObject() : NPObject(), parent(nullptr), invalidated(false) {
    MOZ_COUNT_CTOR(ChildNPObject);
  }

  MOZ_COUNTED_DTOR(ChildNPObject)

  // |parent| is always valid as long as the actor is alive. Once the actor is
  // destroyed this will be set to null.
  PluginScriptableObjectChild* parent;
  bool invalidated;
};

class PluginScriptableObjectChild : public PPluginScriptableObjectChild {
  friend class PluginInstanceChild;

 public:
  explicit PluginScriptableObjectChild(ScriptableObjectType aType);
  virtual ~PluginScriptableObjectChild();

  bool InitializeProxy();

  void InitializeLocal(NPObject* aObject);

  mozilla::ipc::IPCResult AnswerInvalidate();

  mozilla::ipc::IPCResult AnswerHasMethod(const PluginIdentifier& aId,
                                          bool* aHasMethod);

  mozilla::ipc::IPCResult AnswerInvoke(const PluginIdentifier& aId,
                                       nsTArray<Variant>&& aArgs,
                                       Variant* aResult, bool* aSuccess);

  mozilla::ipc::IPCResult AnswerInvokeDefault(nsTArray<Variant>&& aArgs,
                                              Variant* aResult, bool* aSuccess);

  mozilla::ipc::IPCResult AnswerHasProperty(const PluginIdentifier& aId,
                                            bool* aHasProperty);

  mozilla::ipc::IPCResult AnswerGetChildProperty(const PluginIdentifier& aId,
                                                 bool* aHasProperty,
                                                 bool* aHasMethod,
                                                 Variant* aResult,
                                                 bool* aSuccess);

  mozilla::ipc::IPCResult AnswerSetProperty(const PluginIdentifier& aId,
                                            const Variant& aValue,
                                            bool* aSuccess);

  mozilla::ipc::IPCResult AnswerRemoveProperty(const PluginIdentifier& aId,
                                               bool* aSuccess);

  mozilla::ipc::IPCResult AnswerEnumerate(
      nsTArray<PluginIdentifier>* aProperties, bool* aSuccess);

  mozilla::ipc::IPCResult AnswerConstruct(nsTArray<Variant>&& aArgs,
                                          Variant* aResult, bool* aSuccess);

  mozilla::ipc::IPCResult RecvProtect();

  mozilla::ipc::IPCResult RecvUnprotect();

  NPObject* GetObject(bool aCanResurrect);

  static const NPClass* GetClass() { return &sNPClass; }

  PluginInstanceChild* GetInstance() const { return mInstance; }

  // Protect only affects LocalObject actors. It is called by the
  // ProtectedVariant/Actor helper classes before the actor is used as an
  // argument to an IPC call and when the parent process resurrects a
  // proxy object to the NPObject associated with this actor.
  void Protect();

  // Unprotect only affects LocalObject actors. It is called by the
  // ProtectedVariant/Actor helper classes after the actor is used as an
  // argument to an IPC call and when the parent process is no longer using
  // this actor.
  void Unprotect();

  // DropNPObject is only used for Proxy actors and is called when the child
  // process is no longer using the NPObject associated with this actor. The
  // parent process may subsequently use this actor again in which case a new
  // NPObject will be created and associated with this actor (see
  // ResurrectProxyObject).
  void DropNPObject();

  /**
   * After NPP_Destroy, all NPObjects associated with an instance are
   * destroyed. We are informed of this destruction. This should only be called
   * on Local actors.
   */
  void NPObjectDestroyed();

  bool Evaluate(NPString* aScript, NPVariant* aResult);

  ScriptableObjectType Type() const { return mType; }

 private:
  struct StoredIdentifier {
    nsCString mIdentifier;
    nsAutoRefCnt mRefCnt;
    bool mPermanent;

    nsrefcnt AddRef() {
      ++mRefCnt;
      return mRefCnt;
    }

    nsrefcnt Release() {
      --mRefCnt;
      if (mRefCnt == 0) {
        delete this;
        return 0;
      }
      return mRefCnt;
    }

    explicit StoredIdentifier(const nsCString& aIdentifier)
        : mIdentifier(aIdentifier), mRefCnt(), mPermanent(false) {
      MOZ_COUNT_CTOR(StoredIdentifier);
    }

    MOZ_COUNTED_DTOR(StoredIdentifier)
  };

 public:
  class MOZ_STACK_CLASS StackIdentifier {
   public:
    explicit StackIdentifier(const PluginIdentifier& aIdentifier);
    explicit StackIdentifier(NPIdentifier aIdentifier);
    ~StackIdentifier();

    void MakePermanent() {
      if (mStored) {
        mStored->mPermanent = true;
      }
    }
    NPIdentifier ToNPIdentifier() const;

    bool IsString() const {
      return mIdentifier.type() == PluginIdentifier::TnsCString;
    }
    const nsCString& GetString() const { return mIdentifier.get_nsCString(); }

    int32_t GetInt() const { return mIdentifier.get_int32_t(); }

    PluginIdentifier GetIdentifier() const { return mIdentifier; }

   private:
    DISALLOW_COPY_AND_ASSIGN(StackIdentifier);

    PluginIdentifier mIdentifier;
    RefPtr<StoredIdentifier> mStored;
  };

  static void ClearIdentifiers();

  bool RegisterActor(NPObject* aObject);
  void UnregisterActor(NPObject* aObject);

  static PluginScriptableObjectChild* GetActorForNPObject(NPObject* aObject);

  static void RegisterObject(NPObject* aObject, PluginInstanceChild* aInstance);
  static void UnregisterObject(NPObject* aObject);

  static PluginInstanceChild* GetInstanceForNPObject(NPObject* aObject);

  /**
   * Fill PluginInstanceChild.mDeletingHash with all the remaining NPObjects
   * associated with that instance.
   */
  static void NotifyOfInstanceShutdown(PluginInstanceChild* aInstance);

 private:
  static NPObject* ScriptableAllocate(NPP aInstance, NPClass* aClass);

  static void ScriptableInvalidate(NPObject* aObject);

  static void ScriptableDeallocate(NPObject* aObject);

  static bool ScriptableHasMethod(NPObject* aObject, NPIdentifier aName);

  static bool ScriptableInvoke(NPObject* aObject, NPIdentifier aName,
                               const NPVariant* aArgs, uint32_t aArgCount,
                               NPVariant* aResult);

  static bool ScriptableInvokeDefault(NPObject* aObject, const NPVariant* aArgs,
                                      uint32_t aArgCount, NPVariant* aResult);

  static bool ScriptableHasProperty(NPObject* aObject, NPIdentifier aName);

  static bool ScriptableGetProperty(NPObject* aObject, NPIdentifier aName,
                                    NPVariant* aResult);

  static bool ScriptableSetProperty(NPObject* aObject, NPIdentifier aName,
                                    const NPVariant* aValue);

  static bool ScriptableRemoveProperty(NPObject* aObject, NPIdentifier aName);

  static bool ScriptableEnumerate(NPObject* aObject,
                                  NPIdentifier** aIdentifiers,
                                  uint32_t* aCount);

  static bool ScriptableConstruct(NPObject* aObject, const NPVariant* aArgs,
                                  uint32_t aArgCount, NPVariant* aResult);

  NPObject* CreateProxyObject();

  // ResurrectProxyObject is only used with Proxy actors. It is called when the
  // parent process uses an actor whose NPObject was deleted by the child
  // process.
  bool ResurrectProxyObject();

 private:
  PluginInstanceChild* mInstance;
  NPObject* mObject;
  bool mInvalidated;
  int mProtectCount;

  ScriptableObjectType mType;

  static const NPClass sNPClass;

  static StoredIdentifier* HashIdentifier(const nsCString& aIdentifier);
  static void UnhashIdentifier(StoredIdentifier* aIdentifier);

  typedef nsDataHashtable<nsCStringHashKey, RefPtr<StoredIdentifier>>
      IdentifierTable;
  static IdentifierTable sIdentifiers;

  struct NPObjectData : public nsPtrHashKey<NPObject> {
    explicit NPObjectData(const NPObject* key)
        : nsPtrHashKey<NPObject>(key), instance(nullptr), actor(nullptr) {}

    // never nullptr
    PluginInstanceChild* instance;

    // sometimes nullptr (no actor associated with an NPObject)
    PluginScriptableObjectChild* actor;
  };

  /**
   * mObjectMap contains all the currently active NPObjects (from
   * NPN_CreateObject until the final release/dealloc, whether or not an actor
   * is currently associated with the object.
   */
  static nsTHashtable<NPObjectData>* sObjectMap;
};

} /* namespace plugins */
} /* namespace mozilla */

#endif /* dom_plugins_PluginScriptableObjectChild_h */