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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /js/xpconnect/src/XPCString.cpp | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | js/xpconnect/src/XPCString.cpp | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/js/xpconnect/src/XPCString.cpp b/js/xpconnect/src/XPCString.cpp new file mode 100644 index 0000000000..634d7efcbd --- /dev/null +++ b/js/xpconnect/src/XPCString.cpp @@ -0,0 +1,134 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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/. */ + +/* + * Infrastructure for sharing DOMString data with JSStrings. + * + * Importing an nsAString into JS: + * If possible (GetSharedBufferHandle works) use the external string support in + * JS to create a JSString that points to the readable's buffer. We keep a + * reference to the buffer handle until the JSString is finalized. + * + * Exporting a JSString as an nsAReadable: + * Wrap the JSString with a root-holding XPCJSReadableStringWrapper, which roots + * the string and exposes its buffer via the nsAString interface, as + * well as providing refcounting support. + */ + +#include "nscore.h" +#include "nsString.h" +#include "nsStringBuffer.h" +#include "jsapi.h" +#include "xpcpublic.h" + +using namespace JS; + +const XPCStringConvert::LiteralExternalString + XPCStringConvert::sLiteralExternalString; + +const XPCStringConvert::DOMStringExternalString + XPCStringConvert::sDOMStringExternalString; + +const XPCStringConvert::DynamicAtomExternalString + XPCStringConvert::sDynamicAtomExternalString; + +void XPCStringConvert::LiteralExternalString::finalize(char16_t* aChars) const { + // Nothing to do. +} + +size_t XPCStringConvert::LiteralExternalString::sizeOfBuffer( + const char16_t* aChars, mozilla::MallocSizeOf aMallocSizeOf) const { + // This string's buffer is not heap-allocated, so its malloc size is 0. + return 0; +} + +void XPCStringConvert::DOMStringExternalString::finalize( + char16_t* aChars) const { + nsStringBuffer* buf = nsStringBuffer::FromData(aChars); + buf->Release(); +} + +size_t XPCStringConvert::DOMStringExternalString::sizeOfBuffer( + const char16_t* aChars, mozilla::MallocSizeOf aMallocSizeOf) const { + // We promised the JS engine we would not GC. Enforce that: + JS::AutoCheckCannotGC autoCannotGC; + + const nsStringBuffer* buf = + nsStringBuffer::FromData(const_cast<char16_t*>(aChars)); + // We want sizeof including this, because the entire string buffer is owned by + // the external string. But only report here if we're unshared; if we're + // shared then we don't know who really owns this data. + return buf->SizeOfIncludingThisIfUnshared(aMallocSizeOf); +} + +void XPCStringConvert::DynamicAtomExternalString::finalize( + char16_t* aChars) const { + nsDynamicAtom* atom = nsDynamicAtom::FromChars(aChars); + // nsDynamicAtom::Release is always-inline and defined in a translation unit + // we can't get to here. So we need to go through nsAtom::Release to call + // it. + static_cast<nsAtom*>(atom)->Release(); +} + +size_t XPCStringConvert::DynamicAtomExternalString::sizeOfBuffer( + const char16_t* aChars, mozilla::MallocSizeOf aMallocSizeOf) const { + // We return 0 here because NS_AddSizeOfAtoms reports all memory associated + // with atoms in the atom table. + return 0; +} + +// convert a readable to a JSString, copying string data +// static +bool XPCStringConvert::ReadableToJSVal(JSContext* cx, const nsAString& readable, + nsStringBuffer** sharedBuffer, + MutableHandleValue vp) { + *sharedBuffer = nullptr; + + uint32_t length = readable.Length(); + + if (readable.IsLiteral()) { + return StringLiteralToJSVal(cx, readable.BeginReading(), length, vp); + } + + nsStringBuffer* buf = nsStringBuffer::FromString(readable); + if (buf) { + bool shared; + if (!StringBufferToJSVal(cx, buf, length, vp, &shared)) { + return false; + } + if (shared) { + *sharedBuffer = buf; + } + return true; + } + + // blech, have to copy. + JSString* str = JS_NewUCStringCopyN(cx, readable.BeginReading(), length); + if (!str) { + return false; + } + vp.setString(str); + return true; +} + +namespace xpc { + +bool NonVoidStringToJsval(JSContext* cx, nsAString& str, + MutableHandleValue rval) { + nsStringBuffer* sharedBuffer; + if (!XPCStringConvert::ReadableToJSVal(cx, str, &sharedBuffer, rval)) { + return false; + } + + if (sharedBuffer) { + // The string was shared but ReadableToJSVal didn't addref it. + // Move the ownership from str to jsstr. + str.ForgetSharedBuffer(); + } + return true; +} + +} // namespace xpc |