Changeset 162185 in webkit for trunk/Source/JavaScriptCore/API/OpaqueJSString.h

Timestamp:

Jan 16, 2014, 10:50:26 PM (11 years ago)

Author:

[email protected]

Message:

Get rid of OpaqueJSString::deprecatedCharacters()
​https://bugs.webkit.org/show_bug.cgi?id=127161

Reviewed by Sam Weinig.

Handle OpaqueJSString::m_string being either 8-bit or 16-bit and add extra
code paths for the 8-bit cases.

Unfortunately, JSStringGetCharactersPtr is still expected to return a 16-bit character pointer.
Handle this by storing a separate 16-bit string and initializing it on demand when JSStringGetCharactersPtr
is called. This has the nice side effect of making JSStringGetCharactersPtr thread-safe when it wasn't before.
(In theory, someone could have a JSStringRef backed by an 8-bit string and call JSStringGetCharactersPtr on it
causing an unsafe upconversion to a 16-bit string).

• API/JSStringRef.cpp:

(JSStringGetCharactersPtr):
Call OpaqueJSString::characters.

(JSStringGetUTF8CString):
Add a code path that handles 8-bit strings.

(JSStringIsEqual):
Call OpaqueJSString::equal.

• API/JSStringRefCF.cpp:

(JSStringCreateWithCFString):
Reformat the code to use an early return instead of putting most of the code inside the body of an if statement.

(JSStringCopyCFString):
Create an 8-bit CFStringRef if possible.

• API/OpaqueJSString.cpp:

(OpaqueJSString::create):
Use nullptr.

(OpaqueJSString::~OpaqueJSString):
Free m_characters.

(OpaqueJSString::characters):
Do the up-conversion and store the result in m_characters.

(OpaqueJSString::equal):
New helper function.

• API/OpaqueJSString.h:

(OpaqueJSString::is8Bit):
New function that returns whether a string is 8-bit or not.

(OpaqueJSString::characters8):
(OpaqueJSString::characters16):
Add getters.

File:

• trunk/Source/JavaScriptCore/API/OpaqueJSString.h (modified) (5 diffs)

trunk/Source/JavaScriptCore/API/OpaqueJSString.h

@@ -36 +36 @@
 
 struct OpaqueJSString : public ThreadSafeRefCounted<OpaqueJSString> {
-
-    static PassRefPtr<OpaqueJSString> create() // null
+    static PassRefPtr<OpaqueJSString> create()
     {
         return adoptRef(new OpaqueJSString);
@@ -54 +53 @@
     JS_EXPORT_PRIVATE static PassRefPtr<OpaqueJSString> create(const String&);
 
-    const UChar* characters() { return deprecatedCharacters(); } // FIXME: Delete this.
-    const UChar* deprecatedCharacters() { return this ? m_string.deprecatedCharacters() : nullptr; }
+    ~OpaqueJSString();
+
+    bool is8Bit() { return this ? m_string.is8Bit() : false; }
+    const LChar* characters8() { return this ? m_string.characters8() : nullptr; }
+    const UChar* characters16() { return this ? m_string.characters16() : nullptr; }
     unsigned length() { return this ? m_string.length() : 0; }
+
+    const UChar* characters();
 
     JS_EXPORT_PRIVATE String string() const;
     JSC::Identifier identifier(JSC::VM*) const;
+
+    static bool equal(const OpaqueJSString*, const OpaqueJSString*);
 
 private:
@@ -70 +76 @@
     OpaqueJSString(const String& string)
         : m_string(string.isolatedCopy())
+        , m_characters(nullptr)
     {
     }
@@ -75 +82 @@
     OpaqueJSString(const LChar* characters, unsigned length)
         : m_string(characters, length)
+        , m_characters(nullptr)
     {
     }
@@ -80 +88 @@
     OpaqueJSString(const UChar* characters, unsigned length)
         : m_string(characters, length)
+        , m_characters(nullptr)
     {
     }
 
     String m_string;
+
+    // This will be initialized on demand when characters() is called.
+    std::atomic<UChar*> m_characters;
 };