50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
// Copyright 2014 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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// Flow control
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package http2
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// flow is the flow control window's size.
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type flow struct {
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// n is the number of DATA bytes we're allowed to send.
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// A flow is kept both on a conn and a per-stream.
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n int32
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// conn points to the shared connection-level flow that is
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// shared by all streams on that conn. It is nil for the flow
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// that's on the conn directly.
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conn *flow
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}
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func (f *flow) setConnFlow(cf *flow) { f.conn = cf }
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func (f *flow) available() int32 {
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n := f.n
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if f.conn != nil && f.conn.n < n {
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n = f.conn.n
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}
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return n
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}
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func (f *flow) take(n int32) {
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if n > f.available() {
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panic("internal error: took too much")
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}
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f.n -= n
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if f.conn != nil {
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f.conn.n -= n
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}
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}
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// add adds n bytes (positive or negative) to the flow control window.
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// It returns false if the sum would exceed 2^31-1.
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func (f *flow) add(n int32) bool {
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sum := f.n + n
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if (sum > n) == (f.n > 0) {
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f.n = sum
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return true
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}
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return false
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}
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