1 files changed, 170 insertions, 0 deletions
diff --git a/js/src/vm/StringBuffer.cpp b/js/src/vm/StringBuffer.cpp
new file mode 100644
index 000000000..fd8cdbbd5
--- /dev/null
+++ b/js/src/vm/StringBuffer.cpp
@@ -0,0 +1,170 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "vm/StringBuffer.h"
+
+#include "mozilla/Range.h"
+
+#include "jsobjinlines.h"
+
+#include "vm/String-inl.h"
+
+using namespace js;
+
+template <typename CharT, class Buffer>
+static CharT*
+ExtractWellSized(ExclusiveContext* cx, Buffer& cb)
+{
+    size_t capacity = cb.capacity();
+    size_t length = cb.length();
+
+    CharT* buf = cb.extractOrCopyRawBuffer();
+    if (!buf)
+        return nullptr;
+
+    /* For medium/big buffers, avoid wasting more than 1/4 of the memory. */
+    MOZ_ASSERT(capacity >= length);
+    if (length > Buffer::sMaxInlineStorage && capacity - length > length / 4) {
+        CharT* tmp = cx->zone()->pod_realloc<CharT>(buf, capacity, length + 1);
+        if (!tmp) {
+            js_free(buf);
+            ReportOutOfMemory(cx);
+            return nullptr;
+        }
+        buf = tmp;
+    }
+
+    return buf;
+}
+
+char16_t*
+StringBuffer::stealChars()
+{
+    if (isLatin1() && !inflateChars())
+        return nullptr;
+
+    return ExtractWellSized<char16_t>(cx, twoByteChars());
+}
+
+bool
+StringBuffer::inflateChars()
+{
+    MOZ_ASSERT(isLatin1());
+
+    TwoByteCharBuffer twoByte(cx);
+
+    /*
+     * Note: we don't use Vector::capacity() because it always returns a
+     * value >= sInlineCapacity. Since Latin1CharBuffer::sInlineCapacity >
+     * TwoByteCharBuffer::sInlineCapacitychars, we'd always malloc here.
+     */
+    size_t capacity = Max(reserved_, latin1Chars().length());
+    if (!twoByte.reserve(capacity))
+        return false;
+
+    twoByte.infallibleAppend(latin1Chars().begin(), latin1Chars().length());
+
+    cb.destroy();
+    cb.construct<TwoByteCharBuffer>(Move(twoByte));
+    return true;
+}
+
+template <typename CharT, class Buffer>
+static JSFlatString*
+FinishStringFlat(ExclusiveContext* cx, StringBuffer& sb, Buffer& cb)
+{
+    size_t len = sb.length();
+    if (!sb.append('\0'))
+        return nullptr;
+
+    ScopedJSFreePtr<CharT> buf(ExtractWellSized<CharT>(cx, cb));
+    if (!buf)
+        return nullptr;
+
+    JSFlatString* str = NewStringDontDeflate<CanGC>(cx, buf.get(), len);
+    if (!str)
+        return nullptr;
+
+    /*
+     * The allocation was made on a TempAllocPolicy, so account for the string
+     * data on the string's zone.
+     */
+    str->zone()->updateMallocCounter(sizeof(CharT) * len);
+
+    buf.forget();
+    return str;
+}
+
+JSFlatString*
+StringBuffer::finishString()
+{
+    size_t len = length();
+    if (len == 0)
+        return cx->names().empty;
+
+    if (!JSString::validateLength(cx, len))
+        return nullptr;
+
+    JS_STATIC_ASSERT(JSFatInlineString::MAX_LENGTH_TWO_BYTE < TwoByteCharBuffer::InlineLength);
+    JS_STATIC_ASSERT(JSFatInlineString::MAX_LENGTH_LATIN1 < Latin1CharBuffer::InlineLength);
+
+    if (isLatin1()) {
+        if (JSInlineString::lengthFits<Latin1Char>(len)) {
+            mozilla::Range<const Latin1Char> range(latin1Chars().begin(), len);
+            return NewInlineString<CanGC>(cx, range);
+        }
+    } else {
+        if (JSInlineString::lengthFits<char16_t>(len)) {
+            mozilla::Range<const char16_t> range(twoByteChars().begin(), len);
+            return NewInlineString<CanGC>(cx, range);
+        }
+    }
+
+    return isLatin1()
+        ? FinishStringFlat<Latin1Char>(cx, *this, latin1Chars())
+        : FinishStringFlat<char16_t>(cx, *this, twoByteChars());
+}
+
+JSAtom*
+StringBuffer::finishAtom()
+{
+    size_t len = length();
+    if (len == 0)
+        return cx->names().empty;
+
+    if (isLatin1()) {
+        JSAtom* atom = AtomizeChars(cx, latin1Chars().begin(), len);
+        latin1Chars().clear();
+        return atom;
+    }
+
+    JSAtom* atom = AtomizeChars(cx, twoByteChars().begin(), len);
+    twoByteChars().clear();
+    return atom;
+}
+
+bool
+js::ValueToStringBufferSlow(JSContext* cx, const Value& arg, StringBuffer& sb)
+{
+    RootedValue v(cx, arg);
+    if (!ToPrimitive(cx, JSTYPE_STRING, &v))
+        return false;
+
+    if (v.isString())
+        return sb.append(v.toString());
+    if (v.isNumber())
+        return NumberValueToStringBuffer(cx, v, sb);
+    if (v.isBoolean())
+        return BooleanToStringBuffer(v.toBoolean(), sb);
+    if (v.isNull())
+        return sb.append(cx->names().null);
+    if (v.isSymbol()) {
+        JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_SYMBOL_TO_STRING);
+        return false;
+    }
+    MOZ_ASSERT(v.isUndefined());
+    return sb.append(cx->names().undefined);
+}