1 files changed, 134 insertions, 19 deletions

diff --git a/Source/WTF/wtf/text/StringBuilder.cpp b/Source/WTF/wtf/text/StringBuilder.cpp
index c483ba146..436015a43 100644
--- a/Source/WTF/wtf/text/StringBuilder.cpp
+++ b/Source/WTF/wtf/text/StringBuilder.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2010, 2013, 2016 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,6 +28,7 @@
 #include "StringBuilder.h"
 
 #include "IntegerToStringConversion.h"
+#include "MathExtras.h"
 #include "WTFString.h"
 #include <wtf/dtoa.h>
 
@@ -58,12 +59,7 @@ void StringBuilder::reifyString() const
     if (m_length == m_buffer->length())
         m_string = m_buffer.get();
     else
-        m_string = StringImpl::create(m_buffer, 0, m_length);
-
-    if (m_buffer->has16BitShadow() && m_valid16BitShadowLength < m_length)
-        m_buffer->upconvertCharacters(m_valid16BitShadowLength, m_length);
-
-    m_valid16BitShadowLength = m_length;
+        m_string = StringImpl::createSubstringSharingImpl(*m_buffer, 0, m_length);
 }
 
 void StringBuilder::resize(unsigned newSize)
@@ -84,6 +80,7 @@ void StringBuilder::resize(unsigned newSize)
                 allocateBuffer(m_buffer->characters16(), m_buffer->length());
         }
         m_length = newSize;
+        ASSERT(m_buffer->length() >= m_length);
         return;
     }
 
@@ -92,7 +89,7 @@ void StringBuilder::resize(unsigned newSize)
     ASSERT(m_length == m_string.length());
     ASSERT(newSize < m_string.length());
     m_length = newSize;
-    m_string = StringImpl::create(m_string.impl(), 0, newSize);
+    m_string = StringImpl::createSubstringSharingImpl(*m_string.impl(), 0, newSize);
 }
 
 // Allocate a new 8 bit buffer, copying in currentCharacters (these may come from either m_string
@@ -101,12 +98,13 @@ void StringBuilder::allocateBuffer(const LChar* currentCharacters, unsigned requ
 {
     ASSERT(m_is8Bit);
     // Copy the existing data into a new buffer, set result to point to the end of the existing data.
-    RefPtr<StringImpl> buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters8);
+    auto buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters8);
     memcpy(m_bufferCharacters8, currentCharacters, static_cast<size_t>(m_length) * sizeof(LChar)); // This can't overflow.
     
     // Update the builder state.
-    m_buffer = buffer.release();
+    m_buffer = WTFMove(buffer);
     m_string = String();
+    ASSERT(m_buffer->length() == requiredLength);
 }
 
 // Allocate a new 16 bit buffer, copying in currentCharacters (these may come from either m_string
@@ -115,12 +113,13 @@ void StringBuilder::allocateBuffer(const UChar* currentCharacters, unsigned requ
 {
     ASSERT(!m_is8Bit);
     // Copy the existing data into a new buffer, set result to point to the end of the existing data.
-    RefPtr<StringImpl> buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters16);
+    auto buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters16);
     memcpy(m_bufferCharacters16, currentCharacters, static_cast<size_t>(m_length) * sizeof(UChar)); // This can't overflow.
     
     // Update the builder state.
-    m_buffer = buffer.release();
+    m_buffer = WTFMove(buffer);
     m_string = String();
+    ASSERT(m_buffer->length() == requiredLength);
 }
 
 // Allocate a new 16 bit buffer, copying in currentCharacters (which is 8 bit and may come
@@ -128,16 +127,18 @@ void StringBuilder::allocateBuffer(const UChar* currentCharacters, unsigned requ
 void StringBuilder::allocateBufferUpConvert(const LChar* currentCharacters, unsigned requiredLength)
 {
     ASSERT(m_is8Bit);
+    ASSERT(requiredLength >= m_length);
     // Copy the existing data into a new buffer, set result to point to the end of the existing data.
-    RefPtr<StringImpl> buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters16);
+    auto buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters16);
     for (unsigned i = 0; i < m_length; ++i)
         m_bufferCharacters16[i] = currentCharacters[i];
     
     m_is8Bit = false;
     
     // Update the builder state.
-    m_buffer = buffer.release();
+    m_buffer = WTFMove(buffer);
     m_string = String();
+    ASSERT(m_buffer->length() == requiredLength);
 }
 
 template <>
@@ -151,9 +152,10 @@ void StringBuilder::reallocateBuffer<LChar>(unsigned requiredLength)
     ASSERT(m_buffer->is8Bit());
     
     if (m_buffer->hasOneRef())
-        m_buffer = StringImpl::reallocate(m_buffer.release(), requiredLength, m_bufferCharacters8);
+        m_buffer = StringImpl::reallocate(m_buffer.releaseNonNull(), requiredLength, m_bufferCharacters8);
     else
         allocateBuffer(m_buffer->characters8(), requiredLength);
+    ASSERT(m_buffer->length() == requiredLength);
 }
 
 template <>
@@ -166,9 +168,10 @@ void StringBuilder::reallocateBuffer<UChar>(unsigned requiredLength)
     if (m_buffer->is8Bit())
         allocateBufferUpConvert(m_buffer->characters8(), requiredLength);
     else if (m_buffer->hasOneRef())
-        m_buffer = StringImpl::reallocate(m_buffer.release(), requiredLength, m_bufferCharacters16);
+        m_buffer = StringImpl::reallocate(m_buffer.releaseNonNull(), requiredLength, m_bufferCharacters16);
     else
         allocateBuffer(m_buffer->characters16(), requiredLength);
+    ASSERT(m_buffer->length() == requiredLength);
 }
 
 void StringBuilder::reserveCapacity(unsigned newCapacity)
@@ -193,6 +196,7 @@ void StringBuilder::reserveCapacity(unsigned newCapacity)
                 allocateBuffer(m_string.characters16(), newCapacity);
         }
     }
+    ASSERT(!newCapacity || m_buffer->length() >= newCapacity);
 }
 
 // Make 'length' additional capacity be available in m_buffer, update m_string & m_length,
@@ -233,11 +237,12 @@ CharType* StringBuilder::appendUninitializedSlow(unsigned requiredLength)
         reallocateBuffer<CharType>(expandedCapacity(capacity(), requiredLength));
     } else {
         ASSERT(m_string.length() == m_length);
-        allocateBuffer(m_length ? m_string.getCharacters<CharType>() : 0, expandedCapacity(capacity(), requiredLength));
+        allocateBuffer(m_length ? m_string.characters<CharType>() : 0, expandedCapacity(capacity(), requiredLength));
     }
     
     CharType* result = getBufferCharacters<CharType>() + m_length;
     m_length = requiredLength;
+    ASSERT(m_buffer->length() >= m_length);
     return result;
 }
 
@@ -271,10 +276,11 @@ void StringBuilder::append(const UChar* characters, unsigned length)
             allocateBufferUpConvert(m_string.isNull() ? 0 : m_string.characters8(), expandedCapacity(capacity(), requiredLength));
         }
 
-        memcpy(m_bufferCharacters16 + m_length, characters, static_cast<size_t>(length) * sizeof(UChar));        
+        memcpy(m_bufferCharacters16 + m_length, characters, static_cast<size_t>(length) * sizeof(UChar));
         m_length = requiredLength;
     } else
         memcpy(appendUninitialized<UChar>(length), characters, static_cast<size_t>(length) * sizeof(UChar));
+    ASSERT(m_buffer->length() >= m_length);
 }
 
 void StringBuilder::append(const LChar* characters, unsigned length)
@@ -300,6 +306,20 @@ void StringBuilder::append(const LChar* characters, unsigned length)
     }
 }
 
+#if USE(CF)
+
+void StringBuilder::append(CFStringRef string)
+{
+    // Fast path: avoid constructing a temporary String when possible.
+    if (auto* characters = CFStringGetCStringPtr(string, kCFStringEncodingISOLatin1)) {
+        append(reinterpret_cast<const LChar*>(characters), CFStringGetLength(string));
+        return;
+    }
+    append(String(string));
+}
+
+#endif
+
 void StringBuilder::appendNumber(int number)
 {
     numberToStringSigned<StringBuilder>(number, this);
@@ -361,8 +381,103 @@ void StringBuilder::shrinkToFit()
             reallocateBuffer<LChar>(m_length);
         else
             reallocateBuffer<UChar>(m_length);
-        m_string = m_buffer.release();
+        m_string = WTFMove(m_buffer);
+    }
+}
+
+template <typename OutputCharacterType, typename InputCharacterType>
+static void appendQuotedJSONStringInternalSlow(OutputCharacterType*& output, const InputCharacterType character)
+{
+    switch (character) {
+    case '\t':
+        *output++ = '\\';
+        *output++ = 't';
+        break;
+    case '\r':
+        *output++ = '\\';
+        *output++ = 'r';
+        break;
+    case '\n':
+        *output++ = '\\';
+        *output++ = 'n';
+        break;
+    case '\f':
+        *output++ = '\\';
+        *output++ = 'f';
+        break;
+    case '\b':
+        *output++ = '\\';
+        *output++ = 'b';
+        break;
+    default:
+        ASSERT(!(character & 0xFF00));
+        *output++ = '\\';
+        *output++ = 'u';
+        *output++ = '0';
+        *output++ = '0';
+        *output++ = upperNibbleToLowercaseASCIIHexDigit(character);
+        *output++ = lowerNibbleToLowercaseASCIIHexDigit(character);
+        break;
+    }
+}
+
+template <typename OutputCharacterType, typename InputCharacterType>
+static void appendQuotedJSONStringInternal(OutputCharacterType*& output, const InputCharacterType* input, unsigned length)
+{
+    for (const InputCharacterType* end = input + length; input != end; ++input) {
+        const InputCharacterType character = *input;
+        if (LIKELY(character != '"' && character != '\\' && character > 0x1F)) {
+            *output++ = character;
+            continue;
+        }
+
+        if (character == '"' || character == '\\') {
+            *output++ = '\\';
+            *output++ = character;
+            continue;
+        }
+
+        appendQuotedJSONStringInternalSlow(output, character);
+    }
+}
+
+void StringBuilder::appendQuotedJSONString(const String& string)
+{
+    // Make sure we have enough buffer space to append this string without having
+    // to worry about reallocating in the middle.
+    // The 2 is for the '"' quotes on each end.
+    // The 6 is for characters that need to be \uNNNN encoded.
+    Checked<unsigned> stringLength = string.length();
+    Checked<unsigned> maximumCapacityRequired = length();
+    maximumCapacityRequired += 2 + stringLength * 6;
+    unsigned allocationSize = maximumCapacityRequired.unsafeGet();
+    // This max() is here to allow us to allocate sizes between the range [2^31, 2^32 - 2] because roundUpToPowerOfTwo(1<<31 + some int smaller than 1<<31) == 0.
+    allocationSize = std::max(allocationSize, roundUpToPowerOfTwo(allocationSize));
+
+    if (is8Bit() && !string.is8Bit())
+        allocateBufferUpConvert(m_bufferCharacters8, allocationSize);
+    else
+        reserveCapacity(allocationSize);
+    ASSERT(m_buffer->length() >= allocationSize);
+
+    if (is8Bit()) {
+        ASSERT(string.is8Bit());
+        LChar* output = m_bufferCharacters8 + m_length;
+        *output++ = '"';
+        appendQuotedJSONStringInternal(output, string.characters8(), string.length());
+        *output++ = '"';
+        m_length = output - m_bufferCharacters8;
+    } else {
+        UChar* output = m_bufferCharacters16 + m_length;
+        *output++ = '"';
+        if (string.is8Bit())
+            appendQuotedJSONStringInternal(output, string.characters8(), string.length());
+        else
+            appendQuotedJSONStringInternal(output, string.characters16(), string.length());
+        *output++ = '"';
+        m_length = output - m_bufferCharacters16;
     }
+    ASSERT(m_buffer->length() >= m_length);
 }
 
 } // namespace WTF