Changeset 123504 in webkit

Timestamp:

Jul 24, 2012, 12:12:42 PM (13 years ago)

Author:

benjamin@webkit.org

Message:

Do not perform 8 to 16bits characters conversion when converting a WTFString to NSString/CFString
​https://bugs.webkit.org/show_bug.cgi?id=90720

Patch by Benjamin Poulain <​bpoulain@apple.com> on 2012-07-24
Reviewed by Geoffrey Garen.

In most String to CFString conversion, we should be able to use the "NoCopy" constructor and have
a relatively cheap conversion from WTF::String to CFString.

When the String is 8 bits, it was converted to 16 bits by getData16SlowCase() because of the call
to String::characters().

This patch adds a path for creating a CFString from a 8bits string using CFStringCreateWithBytes.

This is covered by existing tests.

• platform/text/cf/StringCF.cpp:

(WTF::String::createCFString): CFSTR() create static CFString, it is unecessary to retain it.

• platform/text/cf/StringImplCF.cpp:

(WTF::StringImpl::createCFString): The logic to avoid the StringWrapperCFAllocator has also been simplified.
The allocator creation is now closer to where it is useful.

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/text/cf/StringCF.cpp (modified) (1 diff)
• platform/text/cf/StringImplCF.cpp (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-07-24  Benjamin Poulain  <bpoulain@apple.com>
+
+        Do not perform 8 to 16bits characters conversion when converting a WTFString to NSString/CFString
+        https://bugs.webkit.org/show_bug.cgi?id=90720
+
+        Reviewed by Geoffrey Garen.
+
+        In most String to CFString conversion, we should be able to use the "NoCopy" constructor and have
+        a relatively cheap conversion from WTF::String to CFString.
+
+        When the String is 8 bits, it was converted to 16 bits by getData16SlowCase() because of the call
+        to String::characters().
+
+        This patch adds a path for creating a CFString from a 8bits string using CFStringCreateWithBytes.
+
+        This is covered by existing tests.
+
+        * platform/text/cf/StringCF.cpp:
+        (WTF::String::createCFString): CFSTR() create static CFString, it is unecessary to retain it.
+        * platform/text/cf/StringImplCF.cpp:
+        (WTF::StringImpl::createCFString): The logic to avoid the StringWrapperCFAllocator has also been simplified.
+        The allocator creation is now closer to where it is useful.
+
 2012-07-24  Kentaro Hara  <haraken@chromium.org>
 

trunk/Source/WebCore/platform/text/cf/StringCF.cpp

@@ -46 +46 @@
 {
     if (!m_impl)
-        return static_cast<CFStringRef>(CFRetain(CFSTR("")));
+        return CFSTR("");
 
     return m_impl->createCFString();

trunk/Source/WebCore/platform/text/cf/StringImplCF.cpp

@@ -135 +135 @@
 CFStringRef StringImpl::createCFString()
 {
-    CFAllocatorRef allocator = (m_length && isMainThread()) ? StringWrapperCFAllocator::allocator() : 0;
-    if (!allocator)
-        return CFStringCreateWithCharacters(0, reinterpret_cast<const UniChar*>(characters()), m_length);
+    if (!m_length || !isMainThread()) {
+        if (is8Bit())
+            return CFStringCreateWithBytes(0, reinterpret_cast<const UInt8*>(characters8()), m_length, kCFStringEncodingISOLatin1, false);
+        return CFStringCreateWithCharacters(0, reinterpret_cast<const UniChar*>(characters16()), m_length);
+    }
+    CFAllocatorRef allocator = StringWrapperCFAllocator::allocator();
 
     // Put pointer to the StringImpl in a global so the allocator can store it with the CFString.
@@ -143 +146 @@
     StringWrapperCFAllocator::currentString = this;
 
-    CFStringRef string = CFStringCreateWithCharactersNoCopy(allocator, reinterpret_cast<const UniChar*>(characters()), m_length, kCFAllocatorNull);
+    CFStringRef string;
+    if (is8Bit())
+        string = CFStringCreateWithBytesNoCopy(allocator, reinterpret_cast<const UInt8*>(characters8()), m_length, kCFStringEncodingISOLatin1, false, kCFAllocatorNull);
+    else
+        string = CFStringCreateWithCharactersNoCopy(allocator, reinterpret_cast<const UniChar*>(characters16()), m_length, kCFAllocatorNull);
 
     // The allocator cleared the global when it read it, but also clear it here just in case.