From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- js/xpconnect/src/XPCSelfHostedShmem.h | 89 +++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 js/xpconnect/src/XPCSelfHostedShmem.h (limited to 'js/xpconnect/src/XPCSelfHostedShmem.h') diff --git a/js/xpconnect/src/XPCSelfHostedShmem.h b/js/xpconnect/src/XPCSelfHostedShmem.h new file mode 100644 index 0000000000..0fcb1ed05c --- /dev/null +++ b/js/xpconnect/src/XPCSelfHostedShmem.h @@ -0,0 +1,89 @@ +/* -*- 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/. */ + +#ifndef xpcselfhostedshmem_h___ +#define xpcselfhostedshmem_h___ + +#include "base/shared_memory.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/UniquePtrExtensions.h" +#include "mozilla/Span.h" +#include "mozilla/StaticPtr.h" +#include "nsIMemoryReporter.h" +#include "nsIObserver.h" +#include "nsIThread.h" + +namespace xpc { + +// This class is a singleton which holds a file-mapping of the Self Hosted +// Stencil XDR, to be shared by the parent process with all the child processes. +// +// It is either initialized by the parent process by monitoring when the Self +// hosted stencil is produced, or by the content process by reading a shared +// memory-mapped file. +class SelfHostedShmem final : public nsIMemoryReporter { + public: + NS_DECL_THREADSAFE_ISUPPORTS + NS_DECL_NSIMEMORYREPORTER + + // NOTE: This type is identical to JS::SelfHostedCache, but we repeat it to + // avoid including JS engine API in ipc code. + using ContentType = mozilla::Span; + + static SelfHostedShmem& GetSingleton(); + + // Initialize this singleton with the content of the Self-hosted Stencil XDR. + // This will be used to initialize the shared memory which would hold a copy. + // + // This function is not thread-safe and should be call at most once and from + // the main thread. + void InitFromParent(ContentType aXdr); + + // Initialize this singleton with the content coming from the parent process, + // using a file handle which maps to the memory pages of the parent process. + // + // This function is not thread-safe and should be call at most once and from + // the main thread. + [[nodiscard]] bool InitFromChild(base::SharedMemoryHandle aHandle, + size_t aLen); + + // Return a span over the read-only XDR content of the self-hosted stencil. + ContentType Content() const; + + // Return the file handle which is under which the content is mapped. + const mozilla::UniqueFileHandle& Handle() const; + + // Register this class to the memory reporter service. + void InitMemoryReporter(); + + // Unregister this class from the memory reporter service, and delete the + // memory associated with the shared memory. As the memory is borrowed by the + // JS engine, this function should be called after JS_Shutdown. + // + // NOTE: This is not using the Observer service which would call Shutdown + // while JS code might still be running during shutdown process. + static void Shutdown(); + + private: + SelfHostedShmem() = default; + ~SelfHostedShmem() = default; + + static mozilla::StaticRefPtr sSelfHostedXdr; + + // read-only file Handle used to transfer from the parent process to content + // processes. + mozilla::UniqueFileHandle mHandle; + + // Shared memory used by JS runtime initialization. + mozilla::UniquePtr mMem; + + // Length of the content within the shared memory. + size_t mLen = 0; +}; + +} // namespace xpc + +#endif // !xpcselfhostedshmem_h___ -- cgit v1.2.3