1 files changed, 102 insertions, 0 deletions
diff --git a/dom/cache/Action.h b/dom/cache/Action.h
new file mode 100644
index 0000000000..1219c58e24
--- /dev/null
+++ b/dom/cache/Action.h
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 mozilla_dom_cache_Action_h
+#define mozilla_dom_cache_Action_h
+
+#include "mozilla/Atomics.h"
+#include "mozilla/dom/cache/Types.h"
+#include "mozilla/dom/SafeRefPtr.h"
+#include "nsISupportsImpl.h"
+
+class mozIStorageConnection;
+
+namespace mozilla::dom::cache {
+
+class Action : public SafeRefCounted<Action> {
+ public:
+  class Resolver {
+   public:
+    Resolver& operator=(const Resolver& aRHS) = delete;
+
+    // Note: Action must drop Resolver ref after calling Resolve()!
+    // Note: Must be called on the same thread used to execute
+    //       Action::RunOnTarget().
+    virtual void Resolve(nsresult aRv) = 0;
+
+    inline SafeRefPtr<Action::Resolver> SafeRefPtrFromThis() {
+      return SafeRefPtr<Action::Resolver>{this, AcquireStrongRefFromRawPtr{}};
+    }
+
+    NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+  };
+
+  // Class containing data that can be opportunistically shared between
+  // multiple Actions running on the same thread/Context.  In theory
+  // this could be abstracted to a generic key/value map, but for now
+  // just explicitly provide accessors for the data we need.
+  class Data {
+   public:
+    virtual mozIStorageConnection* GetConnection() const = 0;
+
+    virtual void SetConnection(mozIStorageConnection* aConn) = 0;
+  };
+
+  // virtual because deleted through base class pointer
+  virtual ~Action();
+
+  // Execute operations on the target thread.  Once complete call
+  // Resolver::Resolve().  This can be done sync or async.
+  // Note: Action should hold Resolver ref until its ready to call Resolve().
+  // Note: The "target" thread is determined when the Action is scheduled on
+  //       Context.  The Action should not assume any particular thread is used.
+  virtual void RunOnTarget(
+      SafeRefPtr<Resolver> aResolver,
+      const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata,
+      Data* aOptionalData) = 0;
+
+  // Called on initiating thread when the Action is canceled.  The Action is
+  // responsible for calling Resolver::Resolve() as normal; either with a
+  // normal error code or NS_ERROR_ABORT.  If CancelOnInitiatingThread() is
+  // called after Resolve() has already occurred, then the cancel can be
+  // ignored.
+  //
+  // Cancellation is a best effort to stop processing as soon as possible, but
+  // does not guarantee the Action will not run.
+  //
+  // CancelOnInitiatingThread() may be called more than once.  Subsequent
+  // calls should have no effect.
+  //
+  // Default implementation sets an internal cancellation flag that can be
+  // queried with IsCanceled().
+  virtual void CancelOnInitiatingThread();
+
+  // Executed on the initiating thread and is passed the nsresult given to
+  // Resolver::Resolve().
+  virtual void CompleteOnInitiatingThread(nsresult aRv) {}
+
+  // Executed on the initiating thread.  If this Action will operate on the
+  // given cache ID then override this to return true.
+  virtual bool MatchesCacheId(CacheId aCacheId) const { return false; }
+
+  NS_DECL_OWNINGTHREAD
+  MOZ_DECLARE_REFCOUNTED_TYPENAME(cache::Action)
+
+ protected:
+  Action();
+
+  // Check if this Action has been canceled.  May be called from any thread,
+  // but typically used from the target thread.
+  bool IsCanceled() const;
+
+ private:
+  // Accessible from any thread.
+  Atomic<bool> mCanceled;
+};
+
+}  // namespace mozilla::dom::cache
+
+#endif  // mozilla_dom_cache_Action_h