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:



git-svn-id: svn://svn.chromium.org/blink/trunk@54464 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/JavaScriptCore/ChangeLog

+2010-02-05  Gavin Barraclough  <barraclough@apple.com>
+
+        Reviewed by Geoff Garen.
+
+        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).
+
+        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:
+
 2010-02-05  Kwang Yul Seo  <skyul@company100.net>
 
         Reviewed by Eric Seidel.

third_party/WebKit/JavaScriptCore/JavaScriptCore.exp

@@ -104,7 +104,6 @@ __ZN3JSC11JSByteArray15createStructureENS_7JSValueE
 __ZN3JSC11JSByteArrayC1EPNS_9ExecStateEN3WTF17NonNullPassRefPtrINS_9StructureEEEPNS3_9ByteArrayEPKNS_9ClassInfoE
 __ZN3JSC11ParserArena5resetEv
 __ZN3JSC11UStringImpl12sharedBufferEv
-__ZN3JSC11UStringImpl6s_nullE
 __ZN3JSC11UStringImpl7s_emptyE
 __ZN3JSC11UStringImplD1Ev
 __ZN3JSC11checkSyntaxEPNS_9ExecStateERKNS_10SourceCodeE
@@ -238,6 +237,7 @@ __ZN3JSC7UString4fromEd
 __ZN3JSC7UString4fromEi
 __ZN3JSC7UString4fromEj
 __ZN3JSC7UString4fromEl
+__ZN3JSC7UString9s_nullRepE
 __ZN3JSC7UStringC1EPKc
 __ZN3JSC7UStringC1EPKti
 __ZN3JSC7UStringaSEPKc

third_party/WebKit/JavaScriptCore/debugger/Debugger.cpp

@@ -94,7 +94,7 @@ void Debugger::recompileAllJSFunctions(JSGlobalData* globalData)
     // JavaScript in the inspector.
     SourceProviderMap::const_iterator end = sourceProviders.end();
     for (SourceProviderMap::const_iterator iter = sourceProviders.begin(); iter != end; ++iter)
-        sourceParsed(iter->second, SourceCode(iter->first), -1, 0);
+        sourceParsed(iter->second, SourceCode(iter->first), -1, UString());
 }
 
 JSValue evaluateInGlobalCallFrame(const UString& script, JSValue& exception, JSGlobalObject* globalObject)

third_party/WebKit/JavaScriptCore/debugger/DebuggerCallFrame.cpp

@@ -50,11 +50,11 @@ const UString* DebuggerCallFrame::functionName() const
 UString DebuggerCallFrame::calculatedFunctionName() const
 {
     if (!m_callFrame->codeBlock())
-        return 0;
+        return UString();
     
     JSFunction* function = asFunction(m_callFrame->callee());
     if (!function)
-        return 0;
+        return UString();
     return function->calculatedDisplayName(m_callFrame);
 }
 

third_party/WebKit/JavaScriptCore/parser/Parser.cpp

@@ -50,7 +50,7 @@ void Parser::parse(JSGlobalData* globalData, int* errLine, UString* errMsg)
         errMsg = &defaultErrMsg;
 
     *errLine = -1;
-    *errMsg = 0;
+    *errMsg = UString();
 
     Lexer& lexer = *globalData->lexer;
     lexer.setCode(*m_source, m_arena);

third_party/WebKit/JavaScriptCore/profiler/Profile.cpp

@@ -42,7 +42,7 @@ Profile::Profile(const UString& title, unsigned uid)
 {
     // FIXME: When multi-threading is supported this will be a vector and calls
     // into the profiler will need to know which thread it is executing on.
-    m_head = ProfileNode::create(CallIdentifier("Thread_1", 0, 0), 0, 0);
+    m_head = ProfileNode::create(CallIdentifier("Thread_1", UString(), 0), 0, 0);
 }
 
 Profile::~Profile()

third_party/WebKit/JavaScriptCore/profiler/ProfileGenerator.cpp

@@ -124,7 +124,7 @@ void ProfileGenerator::stopProfiling()
     m_currentNode = m_currentNode->parent();
 
    if (double headSelfTime = m_head->selfTime()) {
-        RefPtr<ProfileNode> idleNode = ProfileNode::create(CallIdentifier(NonJSExecution, 0, 0), m_head.get(), m_head.get());
+        RefPtr<ProfileNode> idleNode = ProfileNode::create(CallIdentifier(NonJSExecution, UString(), 0), m_head.get(), m_head.get());
 
         idleNode->setTotalTime(headSelfTime);
         idleNode->setSelfTime(headSelfTime);

third_party/WebKit/JavaScriptCore/runtime/Error.cpp

@@ -94,7 +94,7 @@ JSObject* Error::create(ExecState* exec, ErrorType type, const UString& message,
 
 JSObject* Error::create(ExecState* exec, ErrorType type, const char* message)
 {
-    return create(exec, type, message, -1, -1, NULL);
+    return create(exec, type, message, -1, -1, UString());
 }
 
 JSObject* throwError(ExecState* exec, JSObject* error)
@@ -105,21 +105,21 @@ JSObject* throwError(ExecState* exec, JSObject* error)
 
 JSObject* throwError(ExecState* exec, ErrorType type)
 {
-    JSObject* error = Error::create(exec, type, UString(), -1, -1, NULL);
+    JSObject* error = Error::create(exec, type, UString(), -1, -1, UString());
     exec->setException(error);
     return error;
 }
 
 JSObject* throwError(ExecState* exec, ErrorType type, const UString& message)
 {
-    JSObject* error = Error::create(exec, type, message, -1, -1, NULL);
+    JSObject* error = Error::create(exec, type, message, -1, -1, UString());
     exec->setException(error);
     return error;
 }
 
 JSObject* throwError(ExecState* exec, ErrorType type, const char* message)
 {
-    JSObject* error = Error::create(exec, type, message, -1, -1, NULL);
+    JSObject* error = Error::create(exec, type, message, -1, -1, UString());
     exec->setException(error);
     return error;
 }

third_party/WebKit/JavaScriptCore/runtime/ExceptionHelpers.cpp

@@ -58,7 +58,7 @@ JSValue createInterruptedExecutionException(JSGlobalData* globalData)
 
 static JSValue createError(ExecState* exec, ErrorType e, const char* msg)
 {
-    return Error::create(exec, e, msg, -1, -1, 0);
+    return Error::create(exec, e, msg, -1, -1, UString());
 }
 
 JSValue createStackOverflowError(ExecState* exec)

third_party/WebKit/JavaScriptCore/runtime/Identifier.cpp

@@ -124,8 +124,9 @@ struct CStringTranslator {
 PassRefPtr<UString::Rep> Identifier::add(JSGlobalData* globalData, const char* c)
 {
     if (!c) {
-        UString::Rep::null().hash();
-        return &UString::Rep::null();
+        UString::Rep* rep = UString::null().rep();
+        rep->hash();
+        return rep;
     }
     if (!c[0]) {
         UString::Rep::empty().hash();

third_party/WebKit/JavaScriptCore/runtime/PropertyNameArray.cpp

@@ -30,7 +30,7 @@ static const size_t setThreshold = 20;
 
 void PropertyNameArray::add(UString::Rep* identifier)
 {
-    ASSERT(identifier == &UString::Rep::null() || identifier == &UString::Rep::empty() || identifier->isIdentifier());
+    ASSERT(identifier == UString::null().rep() || identifier == &UString::Rep::empty() || identifier->isIdentifier());
 
     size_t size = m_data->propertyNameVector().size();
     if (size < setThreshold) {

third_party/WebKit/JavaScriptCore/runtime/UString.cpp

@@ -149,61 +149,26 @@ bool operator==(const CString& c1, const CString& c2)
 // These static strings are immutable, except for rc, whose initial value is chosen to 
 // reduce the possibility of it becoming zero due to ref/deref not being thread-safe.
 static UChar sharedEmptyChar;
-UStringImpl* UStringImpl::s_null;
 UStringImpl* UStringImpl::s_empty;
-UString* UString::nullUString;
+
+UString::Rep* UString::s_nullRep;
+UString* UString::s_nullUString;
 
 void initializeUString()
 {
-    UStringImpl::s_null = new UStringImpl(0, 0, UStringImpl::ConstructStaticString);
     UStringImpl::s_empty = new UStringImpl(&sharedEmptyChar, 0, UStringImpl::ConstructStaticString);
-    UString::nullUString = new UString;
-}
-
-static PassRefPtr<UString::Rep> createRep(const char* c)
-{
-    if (!c)
-        return &UString::Rep::null();
-
-    if (!c[0])
-        return &UString::Rep::empty();
-
-    size_t length = strlen(c);
-    UChar* d;
-    PassRefPtr<UStringImpl> result = UStringImpl::tryCreateUninitialized(length, d);
-    if (!result)
-        return &UString::Rep::null();
-
-    for (size_t i = 0; i < length; i++)
-        d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
-    return result;
-}
-
-static inline PassRefPtr<UString::Rep> createRep(const char* c, int length)
-{
-    if (!c)
-        return &UString::Rep::null();
-
-    if (!length)
-        return &UString::Rep::empty();
-
-    UChar* d;
-    PassRefPtr<UStringImpl> result = UStringImpl::tryCreateUninitialized(length, d);
-    if (!result)
-        return &UString::Rep::null();
 
-    for (int i = 0; i < length; i++)
-        d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
-    return result;
+    UString::s_nullRep = new UStringImpl(0, 0, UStringImpl::ConstructStaticString);
+    UString::s_nullUString = new UString;
 }
 
 UString::UString(const char* c)
-    : m_rep(createRep(c))
+    : m_rep(Rep::create(c))
 {
 }
 
 UString::UString(const char* c, int length)
-    : m_rep(createRep(c, length))
+    : m_rep(Rep::create(c, length))
 {
 }
 
@@ -459,7 +424,7 @@ char* UString::ascii() const
 UString& UString::operator=(const char* c)
 {
     if (!c) {
-        m_rep = &Rep::null();
+        m_rep = s_nullRep;
         return *this;
     }
 
@@ -475,7 +440,7 @@ UString& UString::operator=(const char* c)
         for (int i = 0; i < l; i++)
             d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
     } else
-        makeNull();
+        m_rep = s_nullRep;;
 
     return *this;
 }
@@ -888,16 +853,4 @@ CString UString::UTF8String(bool strict) const
     return CString(buffer.data(), p - buffer.data());
 }
 
-// For use in error handling code paths -- having this not be inlined helps avoid PIC branches to fetch the global on Mac OS X.
-NEVER_INLINE void UString::makeNull()
-{
-    m_rep = &Rep::null();
-}
-
-// For use in error handling code paths -- having this not be inlined helps avoid PIC branches to fetch the global on Mac OS X.
-NEVER_INLINE UString::Rep* UString::nullRep()
-{
-    return &Rep::null();
-}
-
 } // namespace JSC

third_party/WebKit/JavaScriptCore/runtime/UString.h

@@ -157,7 +157,7 @@ namespace JSC {
 
         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(); }
 
         bool is8Bit() const;
@@ -183,10 +183,9 @@ namespace JSC {
 
         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)
             : m_rep(r)
@@ -197,10 +196,10 @@ namespace JSC {
         size_t cost() const { return m_rep->cost(); }
 
     private:
-        void makeNull();
-
         RefPtr<Rep> m_rep;
-        static UString* nullUString;
+
+        JS_EXPORTDATA static Rep* s_nullRep;
+        static UString* s_nullUString;
 
         friend void initializeUString();
         friend bool operator==(const UString&, const UString&);
@@ -255,7 +254,7 @@ namespace JSC {
     int compare(const UString&, const UString&);
 
     inline UString::UString()
-        : m_rep(&Rep::null())
+        : m_rep(s_nullRep)
     {
     }
 

third_party/WebKit/JavaScriptCore/runtime/UStringImpl.cpp

@@ -34,7 +34,44 @@ using namespace WTF::Unicode;
 using namespace std;
 
 namespace JSC {
- 
+
+PassRefPtr<UStringImpl> UStringImpl::create(const char* c)
+{
+    ASSERT(c);
+
+    if (!c[0])
+        return &UStringImpl::empty();
+
+    size_t length = strlen(c);
+    UChar* d;
+    PassRefPtr<UStringImpl> result = UStringImpl::createUninitialized(length, d);
+    for (size_t i = 0; i < length; i++)
+        d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
+    return result;
+}
+
+PassRefPtr<UStringImpl> UStringImpl::create(const char* c, int length)
+{
+    ASSERT(c);
+
+    if (!length)
+        return &UStringImpl::empty();
+
+    UChar* d;
+    PassRefPtr<UStringImpl> result = UStringImpl::createUninitialized(length, d);
+    for (int i = 0; i < length; i++)
+        d[i] = static_cast<unsigned char>(c[i]); // use unsigned char to zero-extend instead of sign-extend
+    return result;
+}
+
+PassRefPtr<UStringImpl> UStringImpl::create(const UChar* buffer, int length)
+{
+    UChar* newBuffer;
+    PassRefPtr<UStringImpl> impl = createUninitialized(length, newBuffer);
+    copyChars(newBuffer, buffer, length);
+    return impl;
+}
+
 SharedUChar* UStringImpl::baseSharedBuffer()
 {
     ASSERT((bufferOwnership() == BufferShared)

third_party/WebKit/JavaScriptCore/runtime/UStringImpl.h

@@ -92,15 +92,9 @@ public:
         return &empty();
     }
 
-    static PassRefPtr<UStringImpl> create(const UChar* buffer, int length)
-    {
-        UChar* newBuffer;
-        if (PassRefPtr<UStringImpl> impl = tryCreateUninitialized(length, newBuffer)) {
-            copyChars(newBuffer, buffer, length);
-            return impl;
-        }
-        return &null();
-    }
+    static PassRefPtr<UStringImpl> create(const char* c);
+    static PassRefPtr<UStringImpl> create(const char* c, int length);
+    static PassRefPtr<UStringImpl> create(const UChar* buffer, int length);
 
     static PassRefPtr<UStringImpl> create(PassRefPtr<UStringImpl> rep, int offset, int length)
     {
@@ -180,7 +174,6 @@ public:
     static unsigned computeHash(const char* s, int length) { ASSERT(length >= 0); return WTF::stringHash(s, length); }
     static unsigned computeHash(const char* s) { return WTF::stringHash(s); }
 
-    static UStringImpl& null() { return *s_null; }
     static UStringImpl& empty() { return *s_empty; }
 
     ALWAYS_INLINE void checkConsistency() const
@@ -288,7 +281,6 @@ private:
     mutable unsigned m_isIdentifier : 1;
     UntypedPtrAndBitfield m_dataBuffer;
 
-    JS_EXPORTDATA static UStringImpl* s_null;
     JS_EXPORTDATA static UStringImpl* s_empty;
 
     friend class JIT;