diff options
Diffstat (limited to 'vendor/github.com/jbenet')
-rw-r--r-- | vendor/github.com/jbenet/go-context/LICENSE | 21 | ||||
-rw-r--r-- | vendor/github.com/jbenet/go-context/io/ctxio.go | 120 |
2 files changed, 141 insertions, 0 deletions
diff --git a/vendor/github.com/jbenet/go-context/LICENSE b/vendor/github.com/jbenet/go-context/LICENSE new file mode 100644 index 0000000000..c7386b3c94 --- /dev/null +++ b/vendor/github.com/jbenet/go-context/LICENSE @@ -0,0 +1,21 @@ +The MIT License (MIT) + +Copyright (c) 2014 Juan Batiz-Benet + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. diff --git a/vendor/github.com/jbenet/go-context/io/ctxio.go b/vendor/github.com/jbenet/go-context/io/ctxio.go new file mode 100644 index 0000000000..b4f2454235 --- /dev/null +++ b/vendor/github.com/jbenet/go-context/io/ctxio.go @@ -0,0 +1,120 @@ +// Package ctxio provides io.Reader and io.Writer wrappers that +// respect context.Contexts. Use these at the interface between +// your context code and your io. +// +// WARNING: read the code. see how writes and reads will continue +// until you cancel the io. Maybe this package should provide +// versions of io.ReadCloser and io.WriteCloser that automatically +// call .Close when the context expires. But for now -- since in my +// use cases I have long-lived connections with ephemeral io wrappers +// -- this has yet to be a need. +package ctxio + +import ( + "io" + + context "golang.org/x/net/context" +) + +type ioret struct { + n int + err error +} + +type Writer interface { + io.Writer +} + +type ctxWriter struct { + w io.Writer + ctx context.Context +} + +// NewWriter wraps a writer to make it respect given Context. +// If there is a blocking write, the returned Writer will return +// whenever the context is cancelled (the return values are n=0 +// and err=ctx.Err().) +// +// Note well: this wrapper DOES NOT ACTUALLY cancel the underlying +// write-- there is no way to do that with the standard go io +// interface. So the read and write _will_ happen or hang. So, use +// this sparingly, make sure to cancel the read or write as necesary +// (e.g. closing a connection whose context is up, etc.) +// +// Furthermore, in order to protect your memory from being read +// _after_ you've cancelled the context, this io.Writer will +// first make a **copy** of the buffer. +func NewWriter(ctx context.Context, w io.Writer) *ctxWriter { + if ctx == nil { + ctx = context.Background() + } + return &ctxWriter{ctx: ctx, w: w} +} + +func (w *ctxWriter) Write(buf []byte) (int, error) { + buf2 := make([]byte, len(buf)) + copy(buf2, buf) + + c := make(chan ioret, 1) + + go func() { + n, err := w.w.Write(buf2) + c <- ioret{n, err} + close(c) + }() + + select { + case r := <-c: + return r.n, r.err + case <-w.ctx.Done(): + return 0, w.ctx.Err() + } +} + +type Reader interface { + io.Reader +} + +type ctxReader struct { + r io.Reader + ctx context.Context +} + +// NewReader wraps a reader to make it respect given Context. +// If there is a blocking read, the returned Reader will return +// whenever the context is cancelled (the return values are n=0 +// and err=ctx.Err().) +// +// Note well: this wrapper DOES NOT ACTUALLY cancel the underlying +// write-- there is no way to do that with the standard go io +// interface. So the read and write _will_ happen or hang. So, use +// this sparingly, make sure to cancel the read or write as necesary +// (e.g. closing a connection whose context is up, etc.) +// +// Furthermore, in order to protect your memory from being read +// _before_ you've cancelled the context, this io.Reader will +// allocate a buffer of the same size, and **copy** into the client's +// if the read succeeds in time. +func NewReader(ctx context.Context, r io.Reader) *ctxReader { + return &ctxReader{ctx: ctx, r: r} +} + +func (r *ctxReader) Read(buf []byte) (int, error) { + buf2 := make([]byte, len(buf)) + + c := make(chan ioret, 1) + + go func() { + n, err := r.r.Read(buf2) + c <- ioret{n, err} + close(c) + }() + + select { + case ret := <-c: + copy(buf, buf2) + return ret.n, ret.err + case <-r.ctx.Done(): + return 0, r.ctx.Err() + } +} |