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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /js/xpconnect/src/XPCSelfHostedShmem.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/xpconnect/src/XPCSelfHostedShmem.h')
-rw-r--r--js/xpconnect/src/XPCSelfHostedShmem.h89
1 files changed, 89 insertions, 0 deletions
diff --git a/js/xpconnect/src/XPCSelfHostedShmem.h b/js/xpconnect/src/XPCSelfHostedShmem.h
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+/* -*- 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<const uint8_t>;
+
+ 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<SelfHostedShmem> 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<base::SharedMemory> mMem;
+
+ // Length of the content within the shared memory.
+ size_t mLen = 0;
+};
+
+} // namespace xpc
+
+#endif // !xpcselfhostedshmem_h___