Revert "NSURLSession Reimplementation (#411)"

This reverts commit 07233534e6.

Source/GSTransferState.h

@@ -0,0 +1,140 @@
+#ifndef	INCLUDED_GSTRANSFERTSTATE_H
+#define	INCLUDED_GSTRANSFERTSTATE_H
+
+#import "GSURLSessionTaskBodySource.h"
+
+
+@class GSURLSessionTaskBodySource;
+@class NSArray;
+@class NSData;
+@class NSMutableData;
+@class NSFileHandle;
+@class NSHTTPURLResponse;
+@class NSURL;
+@class NSURLResponse;
+
+typedef NS_ENUM(NSUInteger, GSParsedResponseHeaderType) {
+    GSParsedResponseHeaderTypePartial,
+    GSParsedResponseHeaderTypeComplete
+};
+
+/*
+ * A native protocol like HTTP header being parsed.
+ *
+ * It can either be complete (i.e. the final CR LF CR LF has been
+ * received), or partial.
+ */
+@interface GSParsedResponseHeader: NSObject
+{
+  NSArray                     *_lines;
+  GSParsedResponseHeaderType  _type;
+}
+
+- (GSParsedResponseHeaderType) type;
+
+/*
+ * Parse a header line passed by libcurl.
+ *
+ * These contain the <CRLF> ending and the final line contains nothing but
+ * that ending.
+ * - Returns: Returning nil indicates failure. Otherwise returns a new
+ *   `GSParsedResponseHeader` with the given line added.
+ */
+- (instancetype) byAppendingHeaderLine: (NSData*)data;
+
+- (NSHTTPURLResponse*) createHTTPURLResponseForURL: (NSURL*)URL;
+
+@end
+
+typedef NS_ENUM(NSUInteger, GSDataDrainType) {
+    // Concatenate in-memory
+    GSDataDrainInMemory,
+    // Write to file
+    GSDataDrainTypeToFile,
+    // Do nothing. Might be forwarded to delegate
+    GSDataDrainTypeIgnore,
+};
+
+@interface GSDataDrain: NSObject
+{
+  GSDataDrainType _type;
+  NSMutableData   *_data;
+  NSURL           *_fileURL;
+  NSFileHandle    *_fileHandle;
+}
+
+- (GSDataDrainType) type;
+- (void) setType: (GSDataDrainType)type;
+
+- (NSMutableData*) data;
+
+- (NSURL*) fileURL;
+
+- (NSFileHandle*) fileHandle;
+
+@end
+
+/*
+ * State related to an ongoing transfer.
+ *
+ * This contains headers received so far, body data received so far, etc.
+ *
+ * There's a strict 1-to-1 relationship between a `GSEasyHandle` and a
+ * `GSTransferState`.
+ */
+@interface GSTransferState: NSObject
+{
+  NSURL                           *_url; // The URL that's being requested
+  GSParsedResponseHeader          *_parsedResponseHeader; // Raw headers received.
+  NSURLResponse                   *_response; // Once the headers is complete, this will contain the response
+  id<GSURLSessionTaskBodySource>  _requestBodySource; // The body data to be sent in the request
+  GSDataDrain                     *_bodyDataDrain; // Body data received
+  BOOL                            _isHeaderComplete;
+}
+
+// Transfer state that can receive body data, but will not send body data.
+- (instancetype) initWithURL: (NSURL*)url
+               bodyDataDrain: (GSDataDrain*)bodyDataDrain;
+
+// Transfer state that sends body data and can receive body data.
+- (instancetype) initWithURL: (NSURL*)url
+               bodyDataDrain: (GSDataDrain*)bodyDataDrain
+                  bodySource: (id<GSURLSessionTaskBodySource>)bodySource;
+
+- (instancetype) initWithURL: (NSURL*)url
+        parsedResponseHeader: (GSParsedResponseHeader*)parsedResponseHeader
+                    response: (NSURLResponse*)response
+                  bodySource: (id<GSURLSessionTaskBodySource>)bodySource
+               bodyDataDrain: (GSDataDrain*)bodyDataDrain;
+
+/*
+ * Append body data
+ */
+- (instancetype) byAppendingBodyData: (NSData*)bodyData;
+
+/*
+ * Appends a header line
+ *
+ * Will set the complete response once the header is complete, i.e. the
+ * return value's `isHeaderComplete` will then by `YES`.
+ *
+ * When a parsing error occurs `error` will be set.
+ */
+- (instancetype) byAppendingHTTPHeaderLineData: (NSData*)data 
+                                         error: (NSError**)error;
+
+- (NSURLResponse*) response;
+
+- (void) setResponse: (NSURLResponse*)response;
+
+- (BOOL) isHeaderComplete; 
+
+- (id<GSURLSessionTaskBodySource>) requestBodySource;
+
+- (GSDataDrain*) bodyDataDrain;
+
+- (NSURL*) URL;
+
+@end
+
+#endif