michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* vim: set ts=8 sts=4 et sw=4 tw=99: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0:  * Infrastructure for sharing DOMString data with JSStrings.
michael@0:  *
michael@0:  * Importing an nsAString into JS:
michael@0:  * If possible (GetSharedBufferHandle works) use the external string support in
michael@0:  * JS to create a JSString that points to the readable's buffer.  We keep a
michael@0:  * reference to the buffer handle until the JSString is finalized.
michael@0:  *
michael@0:  * Exporting a JSString as an nsAReadable:
michael@0:  * Wrap the JSString with a root-holding XPCJSReadableStringWrapper, which roots
michael@0:  * the string and exposes its buffer via the nsAString interface, as
michael@0:  * well as providing refcounting support.
michael@0:  */
michael@0: 
michael@0: #include "nscore.h"
michael@0: #include "nsString.h"
michael@0: #include "nsStringBuffer.h"
michael@0: #include "jsapi.h"
michael@0: #include "xpcpublic.h"
michael@0: 
michael@0: using namespace JS;
michael@0: 
michael@0: // static
michael@0: void
michael@0: XPCStringConvert::FreeZoneCache(JS::Zone *zone)
michael@0: {
michael@0:     // Put the zone user data into an AutoPtr (which will do the cleanup for us),
michael@0:     // and null out the user data (which may already be null).
michael@0:     nsAutoPtr<ZoneStringCache> cache(static_cast<ZoneStringCache*>(JS_GetZoneUserData(zone)));
michael@0:     JS_SetZoneUserData(zone, nullptr);
michael@0: }
michael@0: 
michael@0: // static
michael@0: void
michael@0: XPCStringConvert::ClearZoneCache(JS::Zone *zone)
michael@0: {
michael@0:     ZoneStringCache *cache = static_cast<ZoneStringCache*>(JS_GetZoneUserData(zone));
michael@0:     if (cache) {
michael@0:         cache->mBuffer = nullptr;
michael@0:         cache->mString = nullptr;
michael@0:     }
michael@0: }
michael@0: 
michael@0: // static
michael@0: void
michael@0: XPCStringConvert::FinalizeLiteral(const JSStringFinalizer *fin, jschar *chars)
michael@0: {
michael@0: }
michael@0: 
michael@0: const JSStringFinalizer XPCStringConvert::sLiteralFinalizer =
michael@0:     { XPCStringConvert::FinalizeLiteral };
michael@0: 
michael@0: // static
michael@0: void
michael@0: XPCStringConvert::FinalizeDOMString(const JSStringFinalizer *fin, jschar *chars)
michael@0: {
michael@0:     nsStringBuffer* buf = nsStringBuffer::FromData(chars);
michael@0:     buf->Release();
michael@0: }
michael@0: 
michael@0: const JSStringFinalizer XPCStringConvert::sDOMStringFinalizer =
michael@0:     { XPCStringConvert::FinalizeDOMString };
michael@0: 
michael@0: // convert a readable to a JSString, copying string data
michael@0: // static
michael@0: bool
michael@0: XPCStringConvert::ReadableToJSVal(JSContext *cx,
michael@0:                                   const nsAString &readable,
michael@0:                                   nsStringBuffer** sharedBuffer,
michael@0:                                   MutableHandleValue vp)
michael@0: {
michael@0:     *sharedBuffer = nullptr;
michael@0: 
michael@0:     uint32_t length = readable.Length();
michael@0: 
michael@0:     if (readable.IsLiteral()) {
michael@0:         JSString *str = JS_NewExternalString(cx,
michael@0:                                              static_cast<const jschar*>(readable.BeginReading()),
michael@0:                                              length, &sLiteralFinalizer);
michael@0:         if (!str)
michael@0:             return false;
michael@0:         vp.setString(str);
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     nsStringBuffer *buf = nsStringBuffer::FromString(readable);
michael@0:     if (buf) {
michael@0:         bool shared;
michael@0:         if (!StringBufferToJSVal(cx, buf, length, vp, &shared))
michael@0:             return false;
michael@0:         if (shared)
michael@0:             *sharedBuffer = buf;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     // blech, have to copy.
michael@0:     JSString *str = JS_NewUCStringCopyN(cx, readable.BeginReading(), length);
michael@0:     if (!str)
michael@0:         return false;
michael@0:     vp.setString(str);
michael@0:     return true;
michael@0: }