summaryrefslogtreecommitdiffstats
path: root/image/LookupResult.h
diff options
context:
space:
mode:
Diffstat (limited to 'image/LookupResult.h')
-rw-r--r--image/LookupResult.h90
1 files changed, 90 insertions, 0 deletions
diff --git a/image/LookupResult.h b/image/LookupResult.h
new file mode 100644
index 000000000..b6fc09111
--- /dev/null
+++ b/image/LookupResult.h
@@ -0,0 +1,90 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+/**
+ * LookupResult is the return type of SurfaceCache's Lookup*() functions. It
+ * combines a surface with relevant metadata tracked by SurfaceCache.
+ */
+
+#ifndef mozilla_image_LookupResult_h
+#define mozilla_image_LookupResult_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Move.h"
+#include "ISurfaceProvider.h"
+
+namespace mozilla {
+namespace image {
+
+enum class MatchType : uint8_t
+{
+ NOT_FOUND, // No matching surface and no placeholder.
+ PENDING, // Found a matching placeholder, but no surface.
+ EXACT, // Found a surface that matches exactly.
+ SUBSTITUTE_BECAUSE_NOT_FOUND, // No exact match, but found a similar one.
+ SUBSTITUTE_BECAUSE_PENDING // Found a similar surface and a placeholder
+ // for an exact match.
+};
+
+/**
+ * LookupResult is the return type of SurfaceCache's Lookup*() functions. It
+ * combines a surface with relevant metadata tracked by SurfaceCache.
+ */
+class MOZ_STACK_CLASS LookupResult
+{
+public:
+ explicit LookupResult(MatchType aMatchType)
+ : mMatchType(aMatchType)
+ {
+ MOZ_ASSERT(mMatchType == MatchType::NOT_FOUND ||
+ mMatchType == MatchType::PENDING,
+ "Only NOT_FOUND or PENDING make sense with no surface");
+ }
+
+ LookupResult(LookupResult&& aOther)
+ : mSurface(Move(aOther.mSurface))
+ , mMatchType(aOther.mMatchType)
+ { }
+
+ LookupResult(DrawableSurface&& aSurface, MatchType aMatchType)
+ : mSurface(Move(aSurface))
+ , mMatchType(aMatchType)
+ {
+ MOZ_ASSERT(!mSurface || !(mMatchType == MatchType::NOT_FOUND ||
+ mMatchType == MatchType::PENDING),
+ "Only NOT_FOUND or PENDING make sense with no surface");
+ MOZ_ASSERT(mSurface || mMatchType == MatchType::NOT_FOUND ||
+ mMatchType == MatchType::PENDING,
+ "NOT_FOUND or PENDING do not make sense with a surface");
+ }
+
+ LookupResult& operator=(LookupResult&& aOther)
+ {
+ MOZ_ASSERT(&aOther != this, "Self-move-assignment is not supported");
+ mSurface = Move(aOther.mSurface);
+ mMatchType = aOther.mMatchType;
+ return *this;
+ }
+
+ DrawableSurface& Surface() { return mSurface; }
+ const DrawableSurface& Surface() const { return mSurface; }
+
+ /// @return true if this LookupResult contains a surface.
+ explicit operator bool() const { return bool(mSurface); }
+
+ /// @return what kind of match this is (exact, substitute, etc.)
+ MatchType Type() const { return mMatchType; }
+
+private:
+ LookupResult(const LookupResult&) = delete;
+
+ DrawableSurface mSurface;
+ MatchType mMatchType;
+};
+
+} // namespace image
+} // namespace mozilla
+
+#endif // mozilla_image_LookupResult_h