[webkit-changes] [WebKit/WebKit] cf81ca: Micro-optimize Path IPC serialization / deserializ...

[Chris Dumez]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: cf81ca21f2828619acff44933c6515551b50c3be
      https://github.com/WebKit/WebKit/commit/cf81ca21f2828619acff44933c6515551b50c3be
  Author: Chris Dumez <cdumez at apple.com>
  Date:   2023-06-16 (Fri, 16 Jun 2023)

  Changed paths:
    M Source/WebCore/platform/graphics/Path.cpp
    M Source/WebCore/platform/graphics/Path.h
    M Source/WebCore/platform/graphics/cairo/PathCairo.cpp
    M Source/WebCore/platform/graphics/cg/PathCG.cpp
    M Source/WebKit/Shared/WebCoreArgumentCoders.serialization.in

  Log Message:
  -----------
  Micro-optimize Path IPC serialization / deserialization
https://bugs.webkit.org/show_bug.cgi?id=258220

Reviewed by Wenson Hsieh.

Micro-optimize Path IPC serialization / deserialization:
1. The IPC encoder was first serializing inline data and falling back
   to calling apply() if the data isn't inline. However, apply() would
   check again for various types on inline data before calling
   applySlowCase() for the non-inline data. To optimize this, I renamed
   applySlowCase() to applyIgnoringInlineData() and call it directly
   from the IPC encoder.
2. To detect the end of the path during IPC deserialization, the decoder
   relied on serializing the type of each path Element as a
   std::optional<PathElementType> and we would know we reached the end
   when decoding std::nullopt. This was a bit inefficient was it would
   encode first a boolean (std::optional is set or not) and then a
   uint8_t (actual enum value) for each path Element. To optimize this,
   we now encode the end of the path as an enum value so that we only
   ending a uint8_t for each path element type.

* Source/WebCore/platform/graphics/Path.cpp:
(WebCore::Path::apply const):
* Source/WebCore/platform/graphics/Path.h:
(WebCore::Path::encode const):
(WebCore::Path::decode):
(WebCore::EncodedPathElementType::EncodedPathElementType): Deleted.
(WebCore::EncodedPathElementType::isEndOfPath const): Deleted.
(WebCore::EncodedPathElementType::isValidPathElementType const): Deleted.
(WebCore::EncodedPathElementType::type const): Deleted.
* Source/WebCore/platform/graphics/cairo/PathCairo.cpp:
(WebCore::Path::applyIgnoringInlineData const):
(WebCore::Path::applySlowCase const): Deleted.
* Source/WebCore/platform/graphics/cg/PathCG.cpp:
(WebCore::Path::applyIgnoringInlineData const):
(WebCore::Path::applySlowCase const): Deleted.
* Source/WebKit/Shared/WebCoreArgumentCoders.serialization.in:

Canonical link: https://commits.webkit.org/265260@main