From e68b9d00a6e05b3a941f63ffb696f91e554ac5ec Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 18 Oct 2024 20:33:49 +0200 Subject: Adding upstream version 9.0.3. Signed-off-by: Daniel Baumann --- modules/util/io.go | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 modules/util/io.go (limited to 'modules/util/io.go') diff --git a/modules/util/io.go b/modules/util/io.go new file mode 100644 index 0000000..1559b01 --- /dev/null +++ b/modules/util/io.go @@ -0,0 +1,78 @@ +// Copyright 2021 The Gitea Authors. All rights reserved. +// SPDX-License-Identifier: MIT + +package util + +import ( + "bytes" + "errors" + "io" +) + +// ReadAtMost reads at most len(buf) bytes from r into buf. +// It returns the number of bytes copied. n is only less than len(buf) if r provides fewer bytes. +// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil. +func ReadAtMost(r io.Reader, buf []byte) (n int, err error) { + n, err = io.ReadFull(r, buf) + if err == io.EOF || err == io.ErrUnexpectedEOF { + err = nil + } + return n, err +} + +// ReadWithLimit reads at most "limit" bytes from r into buf. +// If EOF or ErrUnexpectedEOF occurs while reading, err will be nil. +func ReadWithLimit(r io.Reader, n int) (buf []byte, err error) { + return readWithLimit(r, 1024, n) +} + +func readWithLimit(r io.Reader, batch, limit int) ([]byte, error) { + if limit <= batch { + buf := make([]byte, limit) + n, err := ReadAtMost(r, buf) + if err != nil { + return nil, err + } + return buf[:n], nil + } + res := bytes.NewBuffer(make([]byte, 0, batch)) + bufFix := make([]byte, batch) + eof := false + for res.Len() < limit && !eof { + bufTmp := bufFix + if res.Len()+batch > limit { + bufTmp = bufFix[:limit-res.Len()] + } + n, err := io.ReadFull(r, bufTmp) + if err == io.EOF || err == io.ErrUnexpectedEOF { + eof = true + } else if err != nil { + return nil, err + } + if _, err = res.Write(bufTmp[:n]); err != nil { + return nil, err + } + } + return res.Bytes(), nil +} + +// ErrNotEmpty is an error reported when there is a non-empty reader +var ErrNotEmpty = errors.New("not-empty") + +// IsEmptyReader reads a reader and ensures it is empty +func IsEmptyReader(r io.Reader) (err error) { + var buf [1]byte + + for { + n, err := r.Read(buf[:]) + if err != nil { + if err == io.EOF { + return nil + } + return err + } + if n > 0 { + return ErrNotEmpty + } + } +} -- cgit v1.2.3