dom/cache/Action.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_cache_Action_h
   8 #define mozilla_dom_cache_Action_h
   9
  10 #include "CacheCipherKeyManager.h"
  11 #include "mozilla/Atomics.h"
  12 #include "mozilla/dom/cache/Types.h"
  13 #include "mozilla/dom/SafeRefPtr.h"
  14 #include "nsISupportsImpl.h"
  15
  16 class mozIStorageConnection;
  17
  18 namespace mozilla::dom::cache {
  19
  20 class Action : public SafeRefCounted<Action> {
  21  public:
  22   class Resolver {
  23    public:
  24     Resolver& operator=(const Resolver& aRHS) = delete;
  25
  26     // Note: Action must drop Resolver ref after calling Resolve()!
  27     // Note: Must be called on the same thread used to execute
  28     //       Action::RunOnTarget().
  29     virtual void Resolve(nsresult aRv) = 0;
  30
  31     inline SafeRefPtr<Action::Resolver> SafeRefPtrFromThis() {
  32       return SafeRefPtr<Action::Resolver>{this, AcquireStrongRefFromRawPtr{}};
  33     }
  34
  35     NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
  36   };
  37
  38   // Class containing data that can be opportunistically shared between
  39   // multiple Actions running on the same thread/Context.  In theory
  40   // this could be abstracted to a generic key/value map, but for now
  41   // just explicitly provide accessors for the data we need.
  42   class Data {
  43    public:
  44     virtual mozIStorageConnection* GetConnection() const = 0;
  45
  46     virtual void SetConnection(mozIStorageConnection* aConn) = 0;
  47   };
  48
  49   // virtual because deleted through base class pointer
  50   virtual ~Action();
  51
  52   // Execute operations on the target thread.  Once complete call
  53   // Resolver::Resolve().  This can be done sync or async.
  54   // Note: Action should hold Resolver ref until its ready to call Resolve().
  55   // Note: The "target" thread is determined when the Action is scheduled on
  56   //       Context.  The Action should not assume any particular thread is used.
  57   virtual void RunOnTarget(
  58       SafeRefPtr<Resolver> aResolver,
  59       const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata,
  60       Data* aOptionalData, const Maybe<CipherKey>& aMaybeCipherKey) = 0;
  61
  62   // Called on initiating thread when the Action is canceled.  The Action is
  63   // responsible for calling Resolver::Resolve() as normal; either with a
  64   // normal error code or NS_ERROR_ABORT.  If CancelOnInitiatingThread() is
  65   // called after Resolve() has already occurred, then the cancel can be
  66   // ignored.
  67   //
  68   // Cancellation is a best effort to stop processing as soon as possible, but
  69   // does not guarantee the Action will not run.
  70   //
  71   // CancelOnInitiatingThread() may be called more than once.  Subsequent
  72   // calls should have no effect.
  73   //
  74   // Default implementation sets an internal cancellation flag that can be
  75   // queried with IsCanceled().
  76   virtual void CancelOnInitiatingThread();
  77
  78   // Executed on the initiating thread and is passed the nsresult given to
  79   // Resolver::Resolve().
  80   virtual void CompleteOnInitiatingThread(nsresult aRv) {}
  81
  82   // Executed on the initiating thread.  If this Action will operate on the
  83   // given cache ID then override this to return true.
  84   virtual bool MatchesCacheId(CacheId aCacheId) const { return false; }
  85
  86   NS_DECL_OWNINGTHREAD
  87   MOZ_DECLARE_REFCOUNTED_TYPENAME(cache::Action)
  88
  89  protected:
  90   Action();
  91
  92   // Check if this Action has been canceled.  May be called from any thread,
  93   // but typically used from the target thread.
  94   bool IsCanceled() const;
  95
  96  private:
  97   // Accessible from any thread.
  98   Atomic<bool> mCanceled;
  99 };
 100
 101 }  // namespace mozilla::dom::cache
 102
 103 #endif  // mozilla_dom_cache_Action_h