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GeezerVison is showing github.com — gh-129005: Avoid copy in _pyio.FileIO.readinto by cmaloney · Pull Request #129324 · python/cpython

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@cmaloney

@cmaloney cmaloney commented Jan 26, 2025 •
edited by bedevere-app Bot
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os.read allocated and filled a buffer by calling read(2), than that data was copied into the user provied buffer. Read directly into the caller's buffer instead by using os.readinto.

os.readinto uses PyObject_GetBuffer to make sure the passed in buffer is writeable and bytes-like, drop the manual check.

  • Issue: Reduce copies when reading files in pyio, match behavior of _io #129005

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@cmaloney
pythongh-129005: Avoid copy in _pyio.FileIO.readinto
2fbe898 
`os.read` allocated and filled a buffer by calling `read(2)`, than that
data was copied into the user provied buffer. Read directly into the
caller's buffer instead by using `os.readinto`.

`os.readinto` uses `PyObject_GetBuffer` to make sure the passed in
buffer is writeable and bytes-like, drop the manual check.
@bedevere-app bedevere-app Bot added the awaiting review label Jan 26, 2025
@bedevere-app bedevere-app Bot mentioned this pull request Jan 26, 2025
Reduce copies when reading files in pyio, match behavior of _io #129005
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vstinner
vstinner approved these changes Jan 28, 2025
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LGTM

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@bedevere-app bedevere-app Bot added awaiting merge and removed awaiting review labels Jan 28, 2025
@vstinner
vstinner merged commit 180ee43 into python:main Jan 28, 2025
@bedevere-app bedevere-app Bot removed the awaiting merge label Jan 28, 2025
@vstinner

vstinner commented Jan 28, 2025

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Merged, thank you.
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@cmaloney
cmaloney deleted the cmaloney/pyio_to_os_readinto branch January 28, 2025 17:34
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@cmaloney @vstinner
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