AdGuardHome/internal/aghio/limitedreadcloser.go

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Pull request: 2305 limit message size Merge in DNS/adguard-home from 2305-limit-message-size to master Closes #2305. Squashed commit of the following: commit 6edd1e0521277a680f0053308efcf3d9cacc8e62 Author: Eugene Burkov <e.burkov@adguard.com> Date: Mon Nov 23 14:03:36 2020 +0300 aghio: fix final inaccuracies commit 4dd382aaf25132b31eb269749a2cd36daf0cb792 Author: Eugene Burkov <e.burkov@adguard.com> Date: Mon Nov 23 13:59:10 2020 +0300 all: improve code quality commit 060f923f6023d0e6f26441559b7023d5e5f96843 Author: Eugene Burkov <e.burkov@adguard.com> Date: Mon Nov 23 13:10:57 2020 +0300 aghio: add validation to constructor commit f57a2f596f5dc578548241c315c68dce7fc93905 Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 19:19:26 2020 +0300 all: fix minor inaccuracies commit 93462c71725d3d00655a4bd565b77e64451fff60 Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 19:13:23 2020 +0300 home: make test name follow convention commit 4922986ad84481b054479c43b4133a1b97bee86b Merge: 1f5472abc 046ec13fd Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 19:09:01 2020 +0300 Merge branch 'master' into 2305-limit-message-size commit 1f5472abcfa7427f389825fc59eb4253e1e2bfb7 Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 19:08:21 2020 +0300 aghio: improve readability commit 60dc706b093fa22bbf62f13b2341934364ddc4df Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 18:44:08 2020 +0300 home: cover middleware with test commit bedf436b947ca1fa4493af2fc94f1f40beec7c35 Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 17:10:23 2020 +0300 aghio: improved error informativeness commit 682c5da9f21fa330fb3536bb1c112129c91b9990 Author: Eugene Burkov <e.burkov@adguard.com> Date: Fri Nov 20 13:37:51 2020 +0300 all: limit readers for ReadAll dealing with miscellanious data. commit 78c6dd8d90a0a43fe6ee3f9ed4d5fc637b15ba74 Author: Eugene Burkov <e.burkov@adguard.com> Date: Thu Nov 19 20:07:43 2020 +0300 all: handle ReadAll calls dealing with request's bodies. commit bfe1a6faf6468eb44515e2b0ecffa8c51f90b7e8 Author: Eugene Burkov <e.burkov@adguard.com> Date: Thu Nov 19 17:25:34 2020 +0300 home: add middlewares commit bbd1d491b318e6ba07f8af23ad546183383783a8 Merge: 7b77c2cad 62a8fe0b7 Author: Eugene Burkov <e.burkov@adguard.com> Date: Thu Nov 19 16:44:04 2020 +0300 Merge branch 'master' into 2305-limit-message-size commit 7b77c2cad03154177392460982e1d73ee2a30177 Author: Eugene Burkov <e.burkov@adguard.com> Date: Tue Nov 17 15:33:33 2020 +0300 aghio: create package
2020-11-23 11:14:08 +00:00
// Package aghio contains extensions for io package's types and methods
package aghio
import (
"fmt"
"io"
)
// LimitReachedError records the limit and the operation that caused it.
type LimitReachedError struct {
Limit int64
}
// Error implements error interface for LimitReachedError.
// TODO(a.garipov): Think about error string format.
func (lre *LimitReachedError) Error() string {
return fmt.Sprintf("attempted to read more than %d bytes", lre.Limit)
}
// limitedReadCloser is a wrapper for io.ReadCloser with limited reader and
// dealing with agherr package.
type limitedReadCloser struct {
limit int64
n int64
rc io.ReadCloser
}
// Read implements Reader interface.
func (lrc *limitedReadCloser) Read(p []byte) (n int, err error) {
if lrc.n == 0 {
return 0, &LimitReachedError{
Limit: lrc.limit,
}
}
if int64(len(p)) > lrc.n {
p = p[0:lrc.n]
}
n, err = lrc.rc.Read(p)
lrc.n -= int64(n)
return n, err
}
// Close implements Closer interface.
func (lrc *limitedReadCloser) Close() error {
return lrc.rc.Close()
}
// LimitReadCloser wraps ReadCloser to make it's Reader stop with
// ErrLimitReached after n bytes read.
func LimitReadCloser(rc io.ReadCloser, n int64) (limited io.ReadCloser, err error) {
if n < 0 {
return nil, fmt.Errorf("aghio: invalid n in LimitReadCloser: %d", n)
}
return &limitedReadCloser{
limit: n,
n: n,
rc: rc,
}, nil
}