Invalidate session only if access token errors when extending token

Summary:
Currently when there is a Platform API call that has any error or if there is a
connection error, e.g. timeout, the access token is invalidated. This was due to
diff D378197 where any errors call invalidSession. To fix this narrow the
invalidate call to the scenario where the access token has expired when an API call
is made.

For now, only REST API error codes allow us to easily identify an invalid token
(error code 190). A separate diff will be implemented by the Platform team
to provide an error code for Graph API auth token errors.

Test Plan:
Case facebook#1
1/ Login
2/ Tap Graph API
3/ Tap Get your friends
4/ Go off LAN and WiFi
5/ Tap Get your friends

Case facebook#2
1/ Turn WiFi back on
2/ Tap Get your friends
3/ See friends list
4/ Go back to get to Graph API page
5/ Remove app from https://www.facebook.com/settings/?tab=applications
6/ Tap Get your friends

Case facebook#3
1/ Temporarily modified code to force a Graph API error
     //[[delegate facebook] requestWithGraphPath:@"me" andParams:params
andDelegate:self];
     [[delegate facebook] requestWithGraphPath:@"000000" andParams:params
andDelegate:self];
2/ Tap Graph API
3/ Tap Get your information

Before this change, here were the results
Case facebook#1: Session expires message, which is incorrect behavior
Case facebook#2: Session expires message, which is correct behavior
Case facebook#3: Session expires message, which is incorrect behavior

After this change, here are the results
Case facebook#1: Get the Hackbook "Oops something went wrong" message, which is desired
behavior
Case facebook#2: Get the Hackbook "Oops something went wrong" message, which is not
ideal, user should also be logged out
Case facebook#3: Get the Hackbook "Oops something went wrong" message, which is desired
behavior

Reviewers: yariv, jimbru, brent, toddkrabach, jonathan

CC: lshepard, selekman

Differential Revision: https://phabricator.fb.com/D402481

Revert Plan: OK

Task ID: 900407

src/FBRequest.h

@@ -39,6 +39,7 @@ typedef NSUInteger FBRequestState;
   NSMutableData*        _responseText;
   FBRequestState        _state;
   NSError*              _error;
+  BOOL                  _sessionDidExpire;
 }
 
 
@@ -64,6 +65,7 @@ typedef NSUInteger FBRequestState;
 @property(nonatomic,retain) NSURLConnection*  connection;
 @property(nonatomic,retain) NSMutableData* responseText;
 @property(nonatomic,readonly) FBRequestState state;
+@property(nonatomic,readonly) BOOL sessionDidExpire;
 
 /**
  * Error returned by the server in case of request's failure (or nil otherwise).

src/FBRequest.m

@@ -23,13 +23,15 @@
 static NSString* kUserAgent = @"FacebookConnect";
 static NSString* kStringBoundary = @"3i2ndDfv2rTHiSisAbouNdArYfORhtTPEefj3q2f";
 static const int kGeneralErrorCode = 10000;
+static const int kRESTAPIAccessTokenErrorCode = 190;
 
 static const NSTimeInterval kTimeoutInterval = 180.0;
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 @interface FBRequest ()
 @property (nonatomic,readwrite) FBRequestState state;
+@property (nonatomic,readwrite) BOOL sessionDidExpire;
 @end
 
 @implementation FBRequest
@@ -41,6 +43,7 @@ @implementation FBRequest
             connection = _connection,
             responseText = _responseText,
             state = _state,
+            sessionDidExpire = _sessionDidExpire,
             error = _error;
 //////////////////////////////////////////////////////////////////////////////////////////////////
 // class public
@@ -239,10 +242,12 @@ - (id)parseJsonResponse:(NSData *)data error:(NSError **)error {
  *                          fails with error
  */
 - (void)failWithError:(NSError *)error {
+  if ([error code] == kRESTAPIAccessTokenErrorCode) {
+    self.sessionDidExpire = YES;
+  }
   if ([_delegate respondsToSelector:@selector(request:didFailWithError:)]) {
     [_delegate request:self didFailWithError:error];
   }
-  self.state = kFBRequestStateError;
 }
 
 /*
@@ -313,6 +318,7 @@ - (void)connect {
 
   _connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
   self.state = kFBRequestStateLoading;
+  self.sessionDidExpire = NO;
 }
 
 /**
@@ -355,19 +361,15 @@ - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
 
   self.responseText = nil;
   self.connection = nil;
-
-  if (self.state != kFBRequestStateError) {
-    self.state = kFBRequestStateComplete;
-  }
+  self.state = kFBRequestStateComplete;
 }
 
 - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
   [self failWithError:error];
 
   self.responseText = nil;
   self.connection = nil;
-
-  self.state = kFBRequestStateError;
+  self.state = kFBRequestStateComplete;
 }
 
 @end

src/Facebook.m

@@ -182,13 +182,13 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
   if (context == finishedContext) {
     FBRequest* _request = (FBRequest*)object;
     FBRequestState requestState = [_request state];
-    if (requestState == kFBRequestStateError) {
-      [self invalidateSession];
-      if ([self.sessionDelegate respondsToSelector:@selector(fbSessionInvalidated)]) {
-        [self.sessionDelegate fbSessionInvalidated];
+    if (requestState == kFBRequestStateComplete) {
+      if ([_request sessionDidExpire]) {
+        [self invalidateSession];
+        if ([self.sessionDelegate respondsToSelector:@selector(fbSessionInvalidated)]) {
+          [self.sessionDelegate fbSessionInvalidated];
+        }
       }
-    }
-    if (requestState == kFBRequestStateComplete || requestState == kFBRequestStateError) {
       [_request removeObserver:self forKeyPath:requestFinishedKeyPath];
       [_requests removeObject:_request];
     }