83 lines
2.7 KiB
Go
83 lines
2.7 KiB
Go
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// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package poll supports non-blocking I/O on file descriptors with polling.
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// This supports I/O operations that block only a goroutine, not a thread.
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// This is used by the net and os packages.
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// It uses a poller built into the runtime, with support from the
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// runtime scheduler.
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package poll
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import (
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"errors"
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)
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// errNetClosing is the type of the variable ErrNetClosing.
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// This is used to implement the net.Error interface.
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type errNetClosing struct{}
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// Error returns the error message for ErrNetClosing.
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// Keep this string consistent because of issue #4373:
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// since historically programs have not been able to detect
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// this error, they look for the string.
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func (e errNetClosing) Error() string { return "use of closed network connection" }
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func (e errNetClosing) Timeout() bool { return false }
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func (e errNetClosing) Temporary() bool { return false }
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// ErrNetClosing is returned when a network descriptor is used after
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// it has been closed.
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var ErrNetClosing = errNetClosing{}
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// ErrFileClosing is returned when a file descriptor is used after it
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// has been closed.
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var ErrFileClosing = errors.New("use of closed file")
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// ErrNoDeadline is returned when a request is made to set a deadline
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// on a file type that does not use the poller.
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var ErrNoDeadline = errors.New("file type does not support deadline")
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// Return the appropriate closing error based on isFile.
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func errClosing(isFile bool) error {
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if isFile {
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return ErrFileClosing
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}
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return ErrNetClosing
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}
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// ErrDeadlineExceeded is returned for an expired deadline.
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// This is exported by the os package as os.ErrDeadlineExceeded.
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var ErrDeadlineExceeded error = &DeadlineExceededError{}
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// DeadlineExceededError is returned for an expired deadline.
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type DeadlineExceededError struct{}
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// Implement the net.Error interface.
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// The string is "i/o timeout" because that is what was returned
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// by earlier Go versions. Changing it may break programs that
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// match on error strings.
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func (e *DeadlineExceededError) Error() string { return "i/o timeout" }
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func (e *DeadlineExceededError) Timeout() bool { return true }
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func (e *DeadlineExceededError) Temporary() bool { return true }
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// ErrNotPollable is returned when the file or socket is not suitable
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// for event notification.
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var ErrNotPollable = errors.New("not pollable")
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// consume removes data from a slice of byte slices, for writev.
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func consume(v *[][]byte, n int64) {
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for len(*v) > 0 {
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ln0 := int64(len((*v)[0]))
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if ln0 > n {
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(*v)[0] = (*v)[0][n:]
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return
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}
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n -= ln0
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*v = (*v)[1:]
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}
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}
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// TestHookDidWritev is a hook for testing writev.
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var TestHookDidWritev = func(wrote int) {}
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