Changeset 54464 in webkit for trunk/JavaScriptCore/runtime/UString.h

Timestamp:

Feb 6, 2010, 12:55:31 AM (15 years ago)

Author:

[email protected]

Message:

Change UStringImpl::create to CRASH if the string cannot be allocated,
rather than returning a null string (which will behave like a zero-length
string if used).

Reviewed by Geoff Garen.

Also move createRep function from UString to become new overloaded
UStringImpl::create methods. In doing so, bring their behaviour closer to
being in line with WebCore::StringImpl, in removing the behaviour that they
can be used to produce null UStrings (ASSERT the char* provided is non-null).
This behaviour of converting null C-strings to null UStrings is inefficient
(cmompared to just using UString::null()), incompatible with WebCore::StringImpl's
behaviour, and may generate unexpected behaviour, since in many cases a null
UString can be used like an empty string.

With these changes UStringImpl need not have a concept of null impls, we can
start transitioning this to become an implementation detail of UString, that
internally it chooses to use a null-object rather than an actually zero impl
pointer.

• JavaScriptCore.exp:
• debugger/Debugger.cpp:

(JSC::Debugger::recompileAllJSFunctions):

• debugger/DebuggerCallFrame.cpp:

(JSC::DebuggerCallFrame::calculatedFunctionName):

• parser/Parser.cpp:

(JSC::Parser::parse):

• profiler/Profile.cpp:

(JSC::Profile::Profile):

• profiler/ProfileGenerator.cpp:

(JSC::ProfileGenerator::stopProfiling):

• runtime/Error.cpp:

(JSC::Error::create):
(JSC::throwError):

• runtime/ExceptionHelpers.cpp:

(JSC::createError):

• runtime/Identifier.cpp:

(JSC::Identifier::add):

• runtime/PropertyNameArray.cpp:

(JSC::PropertyNameArray::add):

• runtime/UString.cpp:

(JSC::initializeUString):
(JSC::UString::UString):
(JSC::UString::operator=):

• runtime/UString.h:

(JSC::UString::isNull):
(JSC::UString::null):
(JSC::UString::rep):
(JSC::UString::UString):

• runtime/UStringImpl.cpp:

(JSC::UStringImpl::create):

• runtime/UStringImpl.h:

File:

• trunk/JavaScriptCore/runtime/UString.h (modified) (4 diffs)

trunk/JavaScriptCore/runtime/UString.h

@@ -158 +158 @@
         const UChar* data() const { return m_rep->data(); }
 
-        bool isNull() const { return m_rep == &Rep::null(); }
+        bool isNull() const { return m_rep == s_nullRep; }
         bool isEmpty() const { return !m_rep->size(); }
 
@@ -184 +184 @@
         UString substr(int pos = 0, int len = -1) const;
 
-        static const UString& null() { return *nullUString; }
+        static const UString& null() { return *s_nullUString; }
 
         Rep* rep() const { return m_rep.get(); }
-        static Rep* nullRep();
 
         UString(PassRefPtr<Rep> r)
@@ -198 +197 @@
 
     private:
-        void makeNull();
-
         RefPtr<Rep> m_rep;
-        static UString* nullUString;
+
+        JS_EXPORTDATA static Rep* s_nullRep;
+        static UString* s_nullUString;
 
         friend void initializeUString();
@@ -256 +255 @@
 
     inline UString::UString()
-        : m_rep(&Rep::null())
+        : m_rep(s_nullRep)
     {
     }