Support for server push streams

SPDY/SPDYProtocol.h

@@ -12,9 +12,20 @@
 #import <Foundation/Foundation.h>
 #import "SPDYLogger.h"
 
+
+/**
+  NSNotification calls are posted using the NSURL loader thread. Care must be taken to
+  not block or delay the execution of this thread. Any substantive work should be done
+  on a different thread.
+*/
+
+// userInfo has a key "origin", value is an NSString
 extern NSString *const SPDYOriginRegisteredNotification;
 extern NSString *const SPDYOriginUnregisteredNotification;
 
+// userInfo has a key "request", value is an NSURLRequest
+extern NSString *const SPDYPushRequestReceivedNotification;
+
 @class SPDYConfiguration;
 
 @protocol SPDYTLSTrustEvaluator;

SPDY/SPDYProtocol.m

@@ -21,6 +21,7 @@
 #import "SPDYMetadata+Utils.h"
 #import "SPDYOrigin.h"
 #import "SPDYProtocol+Project.h"
+#import "SPDYPushStreamManager.h"
 #import "SPDYSession.h"
 #import "SPDYSessionManager.h"
 #import "SPDYStream.h"
@@ -32,6 +33,7 @@
 NSString *const SPDYSocketErrorDomain = @"SPDYSocketErrorDomain";
 NSString *const SPDYOriginRegisteredNotification = @"SPDYOriginRegisteredNotification";
 NSString *const SPDYOriginUnregisteredNotification = @"SPDYOriginUnregisteredNotification";
+NSString *const SPDYPushRequestReceivedNotification = @"SPDYPushRequestReceivedNotification";
 
 static char *const SPDYConfigQueue = "com.twitter.SPDYConfigQueue";
 
@@ -49,6 +51,7 @@ @interface SPDYAssertionHandler : NSAssertionHandler
 @end
 
 @interface SPDYProtocolContext : NSObject <SPDYProtocolContext>
+- (void)associateWithStream:(SPDYStream *)stream;
 @end
 
 @implementation SPDYAssertionHandler
@@ -120,15 +123,13 @@ @implementation SPDYProtocolContext
     SPDYMetadata *_metadata;
 }
 
-- (instancetype)initWithStream:(SPDYStream *)stream
+- (void)associateWithStream:(SPDYStream *)stream
 {
-    self = [super init];
-    if (self) {
-        _metadata = stream.metadata;
-    }
-    return self;
+    _metadata = stream.metadata;
 }
 
+#pragma mark SPDYProtocolContext protocol
+
 - (SPDYMetadata *)metadata
 {
     return _metadata;
@@ -382,16 +383,14 @@ - (void)startLoading
         origin = aliasedOrigin;
     }
 
-    // Create the stream
-    _stream = [[SPDYStream alloc] initWithProtocol:self];
-    _context = [[SPDYProtocolContext alloc] initWithStream:_stream];
+    // Create the context, but delay stream creation (to allow for looking up push cache
+    // as late as possible). Must associate stream with this instance of the context then.
+    _context = [[SPDYProtocolContext alloc] init];
 
     if (request.SPDYURLSession) {
         [self detectSessionAndTaskThenContinueWithOrigin:origin];
     } else {
-        // Start the stream
-        SPDYSessionManager *manager = [SPDYSessionManager localManagerForOrigin:origin];
-        [manager queueStream:_stream];
+        [self startStreamForOrigin:origin];
     }
 }
 
@@ -435,9 +434,7 @@ - (void)detectSessionAndTaskThenContinueWithOrigin:(SPDYOrigin *)origin
                     }
                 }
 
-                // Start the stream
-                SPDYSessionManager *manager = [SPDYSessionManager localManagerForOrigin:origin];
-                [manager queueStream:_stream];
+                [self startStreamForOrigin:origin];
             }
         };
 
@@ -447,10 +444,27 @@ - (void)detectSessionAndTaskThenContinueWithOrigin:(SPDYOrigin *)origin
     }];
 }
 
+- (void)startStreamForOrigin:(SPDYOrigin *)origin
+{
+    SPDYSessionManager *manager = [SPDYSessionManager localManagerForOrigin:origin];
+
+    // See if this is currently being pushed, and if so, hook it up, else create it
+    _stream = [manager.pushStreamManager streamForProtocol:self];
+    if (_stream != nil) {
+        SPDY_INFO(@"using in-progress push stream %@ for %@", _stream, self.request.URL.absoluteString);
+    } else {
+        _stream = [[SPDYStream alloc] initWithProtocol:self pushStreamManager:manager.pushStreamManager];
+        [manager queueStream:_stream];
+    }
+    [_context associateWithStream:_stream];
+}
+
 - (void)stopLoading
 {
     SPDY_INFO(@"stop loading %@", self.request.URL.absoluteString);
 
+    [_stream.pushStreamManager stopLoadingStream:_stream];
+
     if (_stream && !_stream.closed) {
         [_stream cancel];
     }

SPDY/SPDYPushStreamManager.h

@@ -0,0 +1,25 @@
+//
+//  SPDYPushStreamManager.h
+//  SPDY
+//
+//  Copyright (c) 2014 Twitter, Inc. All rights reserved.
+//  Licensed under the Apache License v2.0
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Created by Kevin Goodier.
+//
+
+#import <Foundation/Foundation.h>
+
+@class SPDYProtocol;
+@class SPDYStream;
+
+@interface SPDYPushStreamManager : NSObject
+
+- (NSUInteger)pushStreamCount;
+- (NSUInteger)associatedStreamCount;
+- (SPDYStream *)streamForProtocol:(SPDYProtocol *)protocol;
+- (void)addStream:(SPDYStream *)stream associatedWithStream:(SPDYStream *)associatedStream;
+- (void)stopLoadingStream:(SPDYStream *)stream;
+
+@end