https://github.com/python/cpython/commit/853a6b7de222964d8cd0e9478cb5c78d490032e6
commit: 853a6b7de222964d8cd0e9478cb5c78d490032e6
branch: main
author: Cody Maloney <[email protected]>
committer: vstinner <[email protected]>
date: 2025-02-02T15:59:15+01:00
summary:
Revert "gh-129005: Align FileIO.readall() allocation (#129458)" (#129572)
This reverts commit f927204f64b3f8dbecec784e05bc8e25d2a78b2e.
files:
D Misc/NEWS.d/next/Library/2025-01-28-21-22-44.gh-issue-129005.h57i9j.rst
M Lib/_pyio.py
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 76a27910da4d5f..023478aa78c6a0 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -1674,31 +1674,22 @@ def readall(self):
except OSError:
pass
- result = bytearray(bufsize)
- bytes_read = 0
+ result = bytearray()
while True:
- if bytes_read >= bufsize:
- # Parallels _io/fileio.c new_buffersize
- if bufsize > 65536:
- addend = bufsize >> 3
- else:
- addend = bufsize + 256
- if addend < DEFAULT_BUFFER_SIZE:
- addend = DEFAULT_BUFFER_SIZE
- bufsize += addend
- result[bytes_read:bufsize] = b'\0'
- assert bufsize - bytes_read > 0, "Should always try and read at
least one byte"
+ if len(result) >= bufsize:
+ bufsize = len(result)
+ bufsize += max(bufsize, DEFAULT_BUFFER_SIZE)
+ n = bufsize - len(result)
try:
- n = os.readinto(self._fd, memoryview(result)[bytes_read:])
+ chunk = os.read(self._fd, n)
except BlockingIOError:
- if bytes_read > 0:
+ if result:
break
return None
- if n == 0: # reached the end of the file
+ if not chunk: # reached the end of the file
break
- bytes_read += n
+ result += chunk
- del result[bytes_read:]
return bytes(result)
def readinto(self, buffer):
diff --git
a/Misc/NEWS.d/next/Library/2025-01-28-21-22-44.gh-issue-129005.h57i9j.rst
b/Misc/NEWS.d/next/Library/2025-01-28-21-22-44.gh-issue-129005.h57i9j.rst
deleted file mode 100644
index c76fb05e196f87..00000000000000
--- a/Misc/NEWS.d/next/Library/2025-01-28-21-22-44.gh-issue-129005.h57i9j.rst
+++ /dev/null
@@ -1,2 +0,0 @@
-``_pyio.FileIO.readall()`` now allocates, resizes, and fills a data buffer
using
-the same algorithm ``_io.FileIO.readall()`` uses.
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