Resolve comments

src/call-stream.ts

@@ -7,7 +7,7 @@ import {Status} from './constants';
 import {Metadata} from './metadata';
 import {ObjectDuplex} from './object-stream';
 import {Filter} from './filter'
-import {FilterStackFactory} from './filter-stack'
+import {FilterStackFactory} from './filter-stack';
 
 const {
   HTTP2_HEADER_STATUS,
@@ -119,7 +119,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
   }
 
   private endCall(status: StatusObject): void {
-    if (!this.finalStatus === null) {
+    if (this.finalStatus === null) {
       this.finalStatus = status;
       this.emit('status', status);
     }
@@ -190,11 +190,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
         } catch (e) {
           metadata = new Metadata();
         }
-        let status: StatusObject = {
+        let status: StatusObject = { code, details, metadata };
-          code: code,
-          details: details,
-          metadata: metadata
-        };
         this.filterStack.receiveTrailers(Promise.resolve(status)).then((finalStatus) => {
           this.endCall(finalStatus);
         }, (error) => {
@@ -213,6 +209,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
           switch(this.readState) {
           case ReadState.NO_DATA:
             this.readCompressFlag = (data.readUInt8(readHead) !== 0);
+            readHead += 1;
             this.readState = ReadState.READING_SIZE;
             this.readPartialSize.fill(0);
             this.readSizeRemaining = 4;
@@ -240,7 +237,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
             // readMessageRemaining >=0 here
             if (this.readMessageRemaining === 0) {
               // At this point, we have read a full message
-              let messageBytes = Buffer.concat(this.readPartialMessage, this.readMessageSize);
+              const messageBytes = Buffer.concat(this.readPartialMessage, this.readMessageSize);
               // TODO(murgatroid99): Add receive message filters
               if (canPush) {
                 if (!this.push(messageBytes)) {
@@ -250,6 +247,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
               } else {
                 this.unpushedReadMessages.push(messageBytes);
               }
+              this.readState = ReadState.NO_DATA;
             }
           }
         }
@@ -295,6 +293,18 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
           metadata: new Metadata()
         });
       });
+      if (!this.pendingRead) {
+        stream.pause();
+      }
+      if (this.pendingWrite) {
+        if (!this.pendingWriteCallback) {
+          throw new Error('Invalid state in write handling code');
+        }
+        stream.write(this.pendingWrite, this.pendingWriteCallback);
+      }
+      if (this.pendingFinalCallback) {
+        stream.end(this.pendingFinalCallback);
+      }
     }
   }
 
@@ -328,8 +338,8 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
       this.pendingRead = true;
     } else {
       while (this.unpushedReadMessages.length > 0) {
-        let nextMessage = this.unpushedReadMessages.shift();
+        const nextMessage = this.unpushedReadMessages.shift();
-        let keepPushing = this.push(nextMessage);
+        const keepPushing = this.push(nextMessage);
         if (nextMessage === null || (!keepPushing)) {
           return;
         }
@@ -345,7 +355,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
   private encodeMessage(message: WriteObject): Buffer {
     /* allocUnsafe doesn't initiate the bytes in the buffer. We are explicitly
      * overwriting every single byte, so that should be fine */
-    let output: Buffer = Buffer.allocUnsafe(message.message.length + 5);
+    const output: Buffer = Buffer.allocUnsafe(message.message.length + 5);
     // TODO(murgatroid99): handle compressed flag appropriately
     output.writeUInt8(0, 0);
     output.writeUInt32BE(message.message.length, 1);
@@ -355,7 +365,7 @@ export class Http2CallStream extends stream.Duplex implements CallStream {
 
   _write(chunk: WriteObject, encoding: string, cb: Function) {
     // TODO(murgatroid99): Add send message filters
-    let encodedMessage = this.encodeMessage(chunk);
+    const encodedMessage = this.encodeMessage(chunk);
     if (this.http2Stream === null) {
       this.pendingWrite = encodedMessage;
       this.pendingWriteCallback = cb;

src/channel-credentials.ts

@@ -103,8 +103,7 @@ class SecureChannelCredentialsImpl extends ChannelCredentialsImpl {
   }
 
   compose(callCredentials: CallCredentials) : ChannelCredentialsImpl {
-    const combinedCallCredentials =
+    const combinedCallCredentials = this.callCredentials.compose(callCredentials);
-      this.callCredentials.compose(callCredentials);
     return new SecureChannelCredentialsImpl(this.secureContext,
       combinedCallCredentials);
   }

src/channel.ts

@@ -82,12 +82,14 @@ export class Http2Channel extends EventEmitter implements Channel {
     } else {
       this.subChannel = http2.connect(this.address, {secureContext});
     }
-    this.subChannel.on('connect', () => {
+    this.subChannel.once('connect', () => {
       this.transitionToState(ConnectivityState.READY);
     });
     this.subChannel.setTimeout(IDLE_TIMEOUT_MS, () => {
       this.goIdle();
     });
+    /* TODO(murgatroid99): add connection-level error handling with exponential
+     * reconnection backoff */
   }
 
   private goIdle(): void {
@@ -155,9 +157,8 @@ export class Http2Channel extends EventEmitter implements Channel {
     }
     let finalOptions: CallStreamOptions = {
       deadline: options.deadline === undefined ? Infinity : options.deadline,
-      credentials: options.credentials === undefined ?
+      credentials: options.credentials || CallCredentials.createEmpty(),
-        CallCredentials.createEmpty() : options.credentials,
+      flags: options.flags || 0
-      flags: options.flags === undefined ? 0 : options.flags
     }
     let stream: Http2CallStream = new Http2CallStream(methodName, finalOptions, this.filterStackFactory);
     this.startHttp2Stream(methodName, stream, metadata);
@@ -169,7 +170,7 @@ export class Http2Channel extends EventEmitter implements Channel {
     if (this.connectivityState === ConnectivityState.READY) {
       setImmediate(callback);
     } else {
-      this.on('connectivityStateChanged', (newState) => {
+      this.once('connectivityStateChanged', (newState) => {
         if (newState === ConnectivityState.READY) {
           callback();
         }

src/compression-filter.ts

@@ -4,19 +4,16 @@ import {Filter, BaseFilter, FilterFactory} from './filter'
 import {Metadata} from './metadata'
 
 export class CompressionFilter extends BaseFilter implements Filter {
-  constructor() {
-    super();
-  }
 
   async sendMetadata(metadata: Promise<Metadata>): Promise<Metadata> {
-    let headers: Metadata = await metadata;
+    const headers: Metadata = await metadata;
     headers.set('grpc-encoding', 'identity');
     headers.set('grpc-accept-encoding', 'identity');
     return headers;
   }
 
   async receiveMetadata(metadata: Promise<Metadata>): Promise<Metadata> {
-    let headers: Metadata = await metadata;
+    const headers: Metadata = await metadata;
     headers.remove('grpc-encoding');
     headers.remove('grpc-accept-encoding');
     return headers;

src/filter-stack.ts

@@ -6,16 +6,16 @@ import {Filter, FilterFactory} from './filter';
 export class FilterStack implements Filter {
   constructor(private readonly filters: Filter[]) {}
 
-  async sendMetadata(metadata: Promise<Metadata>) {
+  sendMetadata(metadata: Promise<Metadata>) {
-    return await flow(map(this.filters, (filter) => filter.sendMetadata.bind(filter)))(metadata);
+    return flow(map(this.filters, (filter) => filter.sendMetadata.bind(filter)))(metadata);
   }
 
-  async receiveMetadata(metadata: Promise<Metadata>) {
+  receiveMetadata(metadata: Promise<Metadata>) {
-    return await flowRight(map(this.filters, (filter) => filter.receiveMetadata.bind(filter)))(metadata);
+    return flowRight(map(this.filters, (filter) => filter.receiveMetadata.bind(filter)))(metadata);
   }
 
-  async receiveTrailers(status: Promise<StatusObject>): Promise<StatusObject> {
+  receiveTrailers(status: Promise<StatusObject>): Promise<StatusObject> {
-    return await flowRight(map(this.filters, (filter) => filter.receiveTrailers.bind(filter)))(status);
+    return flowRight(map(this.filters, (filter) => filter.receiveTrailers.bind(filter)))(status);
   }
 }
 

src/filter.ts

@@ -1,6 +1,9 @@
 import {Metadata} from './metadata'
 import {StatusObject, CallStream} from './call-stream'
 
+/**
+ * Filter classes represent related per-call logic and state that is primarily
+ * used to modify incoming and outgoing data */
 export interface Filter {
   sendMetadata(metadata: Promise<Metadata>): Promise<Metadata>;