[Breakpad iOS] Add a callback on report upload completion.

This CL adds a result callback on report upload completion.
On failure, Breakpad deletes the configuration file and does retry to
upload a report.
Using this callback, the client will be able to log some metrics and to
act on upload failure.

Bug: 954175
Change-Id: I95a3264b65d4c06ba5d8dde8377440d23f1e2081
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/1572661
Reviewed-by: Mark Mentovai <mark@chromium.org>

src/client/mac/sender/uploader.h

@@ -42,6 +42,13 @@ extern NSString *const kGoogleServerType;
 extern NSString *const kSocorroServerType;
 extern NSString *const kDefaultServerType;
 
+// Optional user-defined function that will be called after a network upload
+// of a crash report.
+// |report_id| will be the id returned by the server, or "ERR" if an error
+// occurred.
+// |error| will contain the error, or nil if no error occured.
+typedef void (^UploadCompletionBlock)(NSString *reportId, NSError *error);
+
 @interface Uploader : NSObject {
  @private
   NSMutableDictionary *parameters_;        // Key value pairs of data (STRONG)
@@ -61,6 +68,12 @@ extern NSString *const kDefaultServerType;
                                            // that are uploaded to the
                                            // crash server with the
                                            // minidump.
+  UploadCompletionBlock uploadCompletion_;  // A block called on network upload
+                                            // completion. Parameters are:
+                                            // The report ID returned by the
+                                            // server,
+                                            // the NSError triggered during
+                                            // upload.
 }
 
 - (id)initWithConfigFile:(const char *)configFile;
@@ -86,4 +99,8 @@ extern NSString *const kDefaultServerType;
 // new ID.
 - (void)handleNetworkResponse:(NSData *)data withError:(NSError *)error;
 
+// Sets the callback to be called after uploading a crash report to the server.
+// Only the latest callback registered will be called.
+- (void)setUploadCompletionBlock:(UploadCompletionBlock)uploadCompletion;
+
 @end

src/client/mac/sender/uploader.mm

@@ -511,6 +511,9 @@ NSDictionary *readConfigurationData(const char *configFile) {
     reportID = [[result stringByTrimmingCharactersInSet:trimSet] UTF8String];
     [self logUploadWithID:reportID];
   }
+  if (uploadCompletion_) {
+    uploadCompletion_([NSString stringWithUTF8String:reportID], error);
+  }
 
   // rename the minidump file according to the id returned from the server
   NSString *minidumpDir =
@@ -547,6 +550,11 @@ NSDictionary *readConfigurationData(const char *configFile) {
   return [NSURLQueryItem queryItemWithName:queryItemName value:escapedValue];
 }
 
+//=============================================================================
+- (void)setUploadCompletionBlock:(UploadCompletionBlock)uploadCompletion {
+  uploadCompletion_ = uploadCompletion;
+}
+
 //=============================================================================
 - (void)report {
   NSURL *url = [NSURL URLWithString:[parameters_ objectForKey:@BREAKPAD_URL]];