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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /js/public/WaitCallbacks.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/public/WaitCallbacks.h')
-rw-r--r-- | js/public/WaitCallbacks.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/js/public/WaitCallbacks.h b/js/public/WaitCallbacks.h new file mode 100644 index 0000000000..b79172e6c8 --- /dev/null +++ b/js/public/WaitCallbacks.h @@ -0,0 +1,54 @@ +/* -*- 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 js_WaitCallbacks_h +#define js_WaitCallbacks_h + +#include <stddef.h> +#include <stdint.h> + +#include "jstypes.h" + +struct JS_PUBLIC_API JSRuntime; + +namespace JS { + +/** + * When the JSRuntime is about to block in an Atomics.wait() JS call or in a + * `wait` instruction in WebAssembly, it can notify the host by means of a call + * to BeforeWaitCallback. After the wait, it can notify the host by means of a + * call to AfterWaitCallback. Both callbacks must be null, or neither. + * + * (If you change the callbacks from null to not-null or vice versa while some + * thread on the runtime is in a wait, you will be sorry.) + * + * The argument to the BeforeWaitCallback is a pointer to uninitialized + * stack-allocated working memory of size WAIT_CALLBACK_CLIENT_MAXMEM bytes. + * The caller of SetWaitCallback() must pass the amount of memory it will need, + * and this amount will be checked against that limit and the process will crash + * reliably if the check fails. + * + * The value returned by the BeforeWaitCallback will be passed to the + * AfterWaitCallback. + * + * The AfterWaitCallback will be called even if the wakeup is spurious and the + * thread goes right back to waiting again. Of course the thread will call the + * BeforeWaitCallback once more before it goes to sleep in this situation. + */ + +static constexpr size_t WAIT_CALLBACK_CLIENT_MAXMEM = 32; + +using BeforeWaitCallback = void* (*)(uint8_t* memory); +using AfterWaitCallback = void (*)(void* cookie); + +extern JS_PUBLIC_API void SetWaitCallback(JSRuntime* rt, + BeforeWaitCallback beforeWait, + AfterWaitCallback afterWait, + size_t requiredMemory); + +} // namespace JS + +#endif // js_WaitCallbacks_h |