Add m-esr52 at 52.6.0

1 files changed, 89 insertions, 0 deletions

diff --git a/image/DrawResult.h b/image/DrawResult.h
new file mode 100644
index 0000000000..8240ede26b
--- /dev/null
+++ b/image/DrawResult.h
@@ -0,0 +1,89 @@
+/* -*- 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/. */
+
+#ifndef mozilla_image_DrawResult_h
+#define mozilla_image_DrawResult_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Likely.h"
+
+namespace mozilla {
+namespace image {
+
+/**
+ * An enumeration representing the result of a drawing operation.
+ *
+ * Most users of DrawResult will only be interested in whether the value is
+ * SUCCESS or not. The other values are primarily useful for debugging and error
+ * handling.
+ *
+ * SUCCESS: We successfully drew a completely decoded frame of the requested
+ * size. Drawing again with FLAG_SYNC_DECODE would not change the result.
+ *
+ * INCOMPLETE: We successfully drew a frame that was partially decoded. (Note
+ * that successfully drawing a partially decoded frame may not actually draw any
+ * pixels!) Drawing again with FLAG_SYNC_DECODE would improve the result.
+ *
+ * WRONG_SIZE: We successfully drew a wrongly-sized frame that had to be scaled.
+ * This is only returned if drawing again with FLAG_SYNC_DECODE would improve
+ * the result; if the size requested was larger than the intrinsic size of the
+ * image, for example, we would generally have to scale whether FLAG_SYNC_DECODE
+ * was specified or not, and therefore we would not return WRONG_SIZE.
+ *
+ * NOT_READY: We failed to draw because no decoded version of the image was
+ * available. Drawing again with FLAG_SYNC_DECODE would improve the result.
+ * (Though FLAG_SYNC_DECODE will not necessarily work until after the image's
+ * load event!)
+ *
+ * TEMPORARY_ERROR: We failed to draw due to a temporary error. Drawing may
+ * succeed at a later time.
+ *
+ * BAD_IMAGE: We failed to draw because the image has an error. This is a
+ * permanent condition.
+ *
+ * BAD_ARGS: We failed to draw because bad arguments were passed to draw().
+ */
+enum class MOZ_MUST_USE_TYPE DrawResult : uint8_t
+{
+  SUCCESS,
+  INCOMPLETE,
+  WRONG_SIZE,
+  NOT_READY,
+  TEMPORARY_ERROR,
+  BAD_IMAGE,
+  BAD_ARGS
+};
+
+/**
+ * You can combine DrawResults with &. By analogy to bitwise-&, the result is
+ * DrawResult::SUCCESS only if both operands are DrawResult::SUCCESS. Otherwise,
+ * a failing DrawResult is returned; we favor the left operand's failure when
+ * deciding which failure to return, with the exception that we always prefer
+ * any other kind of failure over DrawResult::BAD_IMAGE, since other failures
+ * are recoverable and we want to know if any recoverable failures occurred.
+ */
+inline DrawResult
+operator&(const DrawResult aLeft, const DrawResult aRight)
+{
+  if (MOZ_LIKELY(aLeft == DrawResult::SUCCESS)) {
+    return aRight;
+  }
+  if (aLeft == DrawResult::BAD_IMAGE && aRight != DrawResult::SUCCESS) {
+    return aRight;
+  }
+  return aLeft;
+}
+
+inline DrawResult&
+operator&=(DrawResult& aLeft, const DrawResult aRight)
+{
+  aLeft = aLeft & aRight;
+  return aLeft;
+}
+
+} // namespace image
+} // namespace mozilla
+
+#endif // mozilla_image_DrawResult_h