fix(ext/node): shared global buffer unlock correctness fix #20314
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mmastrac
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mmastrac
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Aug 28, 2023
| // Try to read again if the underlying stream resource | ||
| // changed. This can happen during TLS upgrades (eg. STARTTLS) | ||
| if (ridBefore != this[kStreamBaseField]!.rid) { | ||
| return this.#read(); | ||
| } | ||
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| buf = new Uint8Array(0); |
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Moved this line for clarity
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aapoalas
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Aug 28, 2023
| bufLocked = true; | ||
| // Lock safety: We must hold this lock until we are certain that buf is no longer used | ||
| // This setup code is a little verbose, but we need to be careful about buffer management | ||
| let buf, locked; |
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nitpick: I'd prep locked to false. I do not know if that helps V8 with optimisation but it might. Also makes TS understand it even in a JS file.
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mmastrac
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Aug 28, 2023
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| server.close(() => { | ||
| p.resolve(); | ||
| finished.resolve(); |
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Note that in the old code, p2 was guaranteed to fire before p so there wasn't much sense in waiting on both.
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Fixes #19831 |
DSergiu
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Aug 29, 2023
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| if (bufLocked) { | ||
| // Already locked, allocate | ||
| buf = new Uint8Array(SUGGESTED_SIZE); | ||
| } else { | ||
| // Not locked, take the buffer + lock | ||
| buf = BUF; | ||
| locked = bufLocked = true; |
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Wouldn't the code be much simpler if you always allocate buf = new Uint8Array(SUGGESTED_SIZE);? locked, bufLocked will be deemed useless.
Is the current shared buffer motivated only by a performance gain? @mmastrac
This was referenced Aug 29, 2023
bartlomieju
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Aug 31, 2023
The fix for #20188 was not entirely correct -- we were unlocking the global buffer incorrectly. This PR introduces a lock state that ensures we only unlock a lock we have taken out.
bartlomieju
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The fix for #20188 was not entirely correct -- we were unlocking the global buffer incorrectly. This PR introduces a lock state that ensures we only unlock a lock we have taken out.