1 files changed, 246 insertions, 0 deletions

diff --git a/vendor/google.golang.org/grpc/transport/control.go b/vendor/google.golang.org/grpc/transport/control.go
new file mode 100644
index 0000000..501eb03
--- /dev/null
+++ b/vendor/google.golang.org/grpc/transport/control.go
@@ -0,0 +1,246 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+        "fmt"
+        "math"
+        "sync"
+        "time"
+
+        "golang.org/x/net/http2"
+)
+
+const (
+        // The default value of flow control window size in HTTP2 spec.
+        defaultWindowSize = 65535
+        // The initial window size for flow control.
+        initialWindowSize             = defaultWindowSize // for an RPC
+        infinity                      = time.Duration(math.MaxInt64)
+        defaultClientKeepaliveTime    = infinity
+        defaultClientKeepaliveTimeout = time.Duration(20 * time.Second)
+        defaultMaxStreamsClient       = 100
+        defaultMaxConnectionIdle      = infinity
+        defaultMaxConnectionAge       = infinity
+        defaultMaxConnectionAgeGrace  = infinity
+        defaultServerKeepaliveTime    = time.Duration(2 * time.Hour)
+        defaultServerKeepaliveTimeout = time.Duration(20 * time.Second)
+        defaultKeepalivePolicyMinTime = time.Duration(5 * time.Minute)
+        // max window limit set by HTTP2 Specs.
+        maxWindowSize = math.MaxInt32
+)
+
+// The following defines various control items which could flow through
+// the control buffer of transport. They represent different aspects of
+// control tasks, e.g., flow control, settings, streaming resetting, etc.
+type windowUpdate struct {
+        streamID  uint32
+        increment uint32
+        flush     bool
+}
+
+func (*windowUpdate) item() {}
+
+type settings struct {
+        ack bool
+        ss  []http2.Setting
+}
+
+func (*settings) item() {}
+
+type resetStream struct {
+        streamID uint32
+        code     http2.ErrCode
+}
+
+func (*resetStream) item() {}
+
+type goAway struct {
+        code      http2.ErrCode
+        debugData []byte
+        headsUp   bool
+        closeConn bool
+}
+
+func (*goAway) item() {}
+
+type flushIO struct {
+}
+
+func (*flushIO) item() {}
+
+type ping struct {
+        ack  bool
+        data [8]byte
+}
+
+func (*ping) item() {}
+
+// quotaPool is a pool which accumulates the quota and sends it to acquire()
+// when it is available.
+type quotaPool struct {
+        c chan int
+
+        mu    sync.Mutex
+        quota int
+}
+
+// newQuotaPool creates a quotaPool which has quota q available to consume.
+func newQuotaPool(q int) *quotaPool {
+        qb := &quotaPool{
+                c: make(chan int, 1),
+        }
+        if q > 0 {
+                qb.c <- q
+        } else {
+                qb.quota = q
+        }
+        return qb
+}
+
+// add cancels the pending quota sent on acquired, incremented by v and sends
+// it back on acquire.
+func (qb *quotaPool) add(v int) {
+        qb.mu.Lock()
+        defer qb.mu.Unlock()
+        select {
+        case n := <-qb.c:
+                qb.quota += n
+        default:
+        }
+        qb.quota += v
+        if qb.quota <= 0 {
+                return
+        }
+        // After the pool has been created, this is the only place that sends on
+        // the channel. Since mu is held at this point and any quota that was sent
+        // on the channel has been retrieved, we know that this code will always
+        // place any positive quota value on the channel.
+        select {
+        case qb.c <- qb.quota:
+                qb.quota = 0
+        default:
+        }
+}
+
+// acquire returns the channel on which available quota amounts are sent.
+func (qb *quotaPool) acquire() <-chan int {
+        return qb.c
+}
+
+// inFlow deals with inbound flow control
+type inFlow struct {
+        mu sync.Mutex
+        // The inbound flow control limit for pending data.
+        limit uint32
+        // pendingData is the overall data which have been received but not been
+        // consumed by applications.
+        pendingData uint32
+        // The amount of data the application has consumed but grpc has not sent
+        // window update for them. Used to reduce window update frequency.
+        pendingUpdate uint32
+        // delta is the extra window update given by receiver when an application
+        // is reading data bigger in size than the inFlow limit.
+        delta uint32
+}
+
+// newLimit updates the inflow window to a new value n.
+// It assumes that n is always greater than the old limit.
+func (f *inFlow) newLimit(n uint32) uint32 {
+        f.mu.Lock()
+        defer f.mu.Unlock()
+        d := n - f.limit
+        f.limit = n
+        return d
+}
+
+func (f *inFlow) maybeAdjust(n uint32) uint32 {
+        if n > uint32(math.MaxInt32) {
+                n = uint32(math.MaxInt32)
+        }
+        f.mu.Lock()
+        defer f.mu.Unlock()
+        // estSenderQuota is the receiver's view of the maximum number of bytes the sender
+        // can send without a window update.
+        estSenderQuota := int32(f.limit - (f.pendingData + f.pendingUpdate))
+        // estUntransmittedData is the maximum number of bytes the sends might not have put
+        // on the wire yet. A value of 0 or less means that we have already received all or
+        // more bytes than the application is requesting to read.
+        estUntransmittedData := int32(n - f.pendingData) // Casting into int32 since it could be negative.
+        // This implies that unless we send a window update, the sender won't be able to send all the bytes
+        // for this message. Therefore we must send an update over the limit since there's an active read
+        // request from the application.
+        if estUntransmittedData > estSenderQuota {
+                // Sender's window shouldn't go more than 2^31 - 1 as speecified in the HTTP spec.
+                if f.limit+n > maxWindowSize {
+                        f.delta = maxWindowSize - f.limit
+                } else {
+                        // Send a window update for the whole message and not just the difference between
+                        // estUntransmittedData and estSenderQuota. This will be helpful in case the message
+                        // is padded; We will fallback on the current available window(at least a 1/4th of the limit).
+                        f.delta = n
+                }
+                return f.delta
+        }
+        return 0
+}
+
+// onData is invoked when some data frame is received. It updates pendingData.
+func (f *inFlow) onData(n uint32) error {
+        f.mu.Lock()
+        defer f.mu.Unlock()
+        f.pendingData += n
+        if f.pendingData+f.pendingUpdate > f.limit+f.delta {
+                return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", f.pendingData+f.pendingUpdate, f.limit)
+        }
+        return nil
+}
+
+// onRead is invoked when the application reads the data. It returns the window size
+// to be sent to the peer.
+func (f *inFlow) onRead(n uint32) uint32 {
+        f.mu.Lock()
+        defer f.mu.Unlock()
+        if f.pendingData == 0 {
+                return 0
+        }
+        f.pendingData -= n
+        if n > f.delta {
+                n -= f.delta
+                f.delta = 0
+        } else {
+                f.delta -= n
+                n = 0
+        }
+        f.pendingUpdate += n
+        if f.pendingUpdate >= f.limit/4 {
+                wu := f.pendingUpdate
+                f.pendingUpdate = 0
+                return wu
+        }
+        return 0
+}
+
+func (f *inFlow) resetPendingUpdate() uint32 {
+        f.mu.Lock()
+        defer f.mu.Unlock()
+        n := f.pendingUpdate
+        f.pendingUpdate = 0
+        return n
+}