1 files changed, 123 insertions, 0 deletions
diff --git a/js/src/vm/SharedImmutableStringsCache.cpp b/js/src/vm/SharedImmutableStringsCache.cpp
new file mode 100644
index 000000000..84422810f
--- /dev/null
+++ b/js/src/vm/SharedImmutableStringsCache.cpp
@@ -0,0 +1,123 @@
+/* -*- 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/SharedImmutableStringsCache-inl.h"
+
+#include "jsstr.h"
+
+namespace js {
+
+SharedImmutableString::SharedImmutableString(
+    ExclusiveData<SharedImmutableStringsCache::Inner>::Guard& locked,
+    SharedImmutableStringsCache::StringBox* box)
+  : cache_(locked)
+  , box_(box)
+{
+    MOZ_ASSERT(box);
+    box->refcount++;
+}
+
+SharedImmutableString::SharedImmutableString(SharedImmutableString&& rhs)
+  : cache_(mozilla::Move(rhs.cache_))
+  , box_(rhs.box_)
+{
+    MOZ_ASSERT(this != &rhs, "self move not allowed");
+    MOZ_ASSERT(rhs.box_);
+    MOZ_ASSERT(rhs.box_->refcount > 0);
+
+    rhs.box_ = nullptr;
+}
+
+SharedImmutableString&
+SharedImmutableString::operator=(SharedImmutableString&& rhs) {
+    this->~SharedImmutableString();
+    new (this) SharedImmutableString(mozilla::Move(rhs));
+    return *this;
+}
+
+SharedImmutableTwoByteString::SharedImmutableTwoByteString(SharedImmutableString&& string)
+  : string_(mozilla::Move(string))
+{ }
+
+SharedImmutableTwoByteString::SharedImmutableTwoByteString(
+    ExclusiveData<SharedImmutableStringsCache::Inner>::Guard& locked,
+    SharedImmutableStringsCache::StringBox* box)
+  : string_(locked, box)
+{
+    MOZ_ASSERT(box->length() % sizeof(char16_t) == 0);
+}
+
+SharedImmutableTwoByteString::SharedImmutableTwoByteString(SharedImmutableTwoByteString&& rhs)
+  : string_(mozilla::Move(rhs.string_))
+{
+    MOZ_ASSERT(this != &rhs, "self move not allowed");
+}
+
+SharedImmutableTwoByteString&
+SharedImmutableTwoByteString::operator=(SharedImmutableTwoByteString&& rhs)
+{
+    this->~SharedImmutableTwoByteString();
+    new (this) SharedImmutableTwoByteString(mozilla::Move(rhs));
+    return *this;
+}
+
+SharedImmutableString::~SharedImmutableString() {
+    if (!box_)
+        return;
+
+    auto locked = cache_.inner_->lock();
+
+    MOZ_ASSERT(box_->refcount > 0);
+
+    box_->refcount--;
+    if (box_->refcount == 0)
+        box_->chars_.reset(nullptr);
+}
+
+SharedImmutableString
+SharedImmutableString::clone() const
+{
+    auto locked = cache_.inner_->lock();
+    MOZ_ASSERT(box_);
+    MOZ_ASSERT(box_->refcount > 0);
+    return SharedImmutableString(locked, box_);
+}
+
+SharedImmutableTwoByteString
+SharedImmutableTwoByteString::clone() const
+{
+    return SharedImmutableTwoByteString(string_.clone());
+}
+
+MOZ_MUST_USE mozilla::Maybe<SharedImmutableString>
+SharedImmutableStringsCache::getOrCreate(OwnedChars&& chars, size_t length)
+{
+    OwnedChars owned(mozilla::Move(chars));
+    MOZ_ASSERT(owned);
+    return getOrCreate(owned.get(), length, [&]() { return mozilla::Move(owned); });
+}
+
+MOZ_MUST_USE mozilla::Maybe<SharedImmutableString>
+SharedImmutableStringsCache::getOrCreate(const char* chars, size_t length)
+{
+    return getOrCreate(chars, length, [&]() { return DuplicateString(chars, length); });
+}
+
+MOZ_MUST_USE mozilla::Maybe<SharedImmutableTwoByteString>
+SharedImmutableStringsCache::getOrCreate(OwnedTwoByteChars&& chars, size_t length)
+{
+    OwnedTwoByteChars owned(mozilla::Move(chars));
+    MOZ_ASSERT(owned);
+    return getOrCreate(owned.get(), length, [&]() { return mozilla::Move(owned); });
+}
+
+MOZ_MUST_USE mozilla::Maybe<SharedImmutableTwoByteString>
+SharedImmutableStringsCache::getOrCreate(const char16_t* chars, size_t length)
+{
+    return getOrCreate(chars, length, [&]() { return DuplicateString(chars, length); });
+}
+
+} // namespace js