Made things consistent re:compression and encoding.

Incorporated review feedback.

Removed the "backwards compatibility" config option.

Source/common/SNTCommonEnums.h

@@ -129,10 +129,10 @@ typedef NS_ENUM(NSInteger, SNTSyncStatusType) {
   SNTSyncStatusTypeUnknown,
 };
 
-typedef NS_ENUM(NSInteger, SNTSyncCompressionEncoding) {
-  SNTSyncCompressionEncodingNone,
-  SNTSyncCompressionEncodingZlib,
-  SNTSyncCompressionEncodingGzip,
+typedef NS_ENUM(NSInteger, SNTSyncContentEncoding) {
+  SNTSyncContentEncodingNone,
+  SNTSyncContentEncodingZlib,
+  SNTSyncContentEncodingGzip,
 };
 
 typedef NS_ENUM(NSInteger, SNTMetricFormatType) {

Source/common/SNTConfigurator.h

@@ -524,9 +524,9 @@
 
 ///
 /// If set, "santactl sync" will use the supplied "Content-Encoding", possible
-/// settings include gzip, deflate, none.
+/// settings include "gzip", "deflate", "none". If empty defaults to "deflate".
 ///
-@property(readonly, nonatomic) SNTSyncCompressionEncoding syncClientContentEncoding;
+@property(readonly, nonatomic) SNTSyncContentEncoding syncClientContentEncoding;
 
 ///
 ///  Contains the FCM project name.

Source/common/SNTConfigurator.m

@@ -109,8 +109,6 @@ @implementation SNTConfigurator
 static NSString *const kIgnoreOtherEndpointSecurityClients = @"IgnoreOtherEndpointSecurityClients";
 static NSString *const kEnableDebugLogging = @"EnableDebugLogging";
 
-static NSString *const kEnableBackwardsCompatibleContentEncoding =
-  @"EnableBackwardsCompatibleContentEncoding";
 static NSString *const kClientContentEncoding = @"SyncClientContentEncoding";
 
 static NSString *const kFCMProject = @"FCMProject";
@@ -223,7 +221,6 @@ - (instancetype)init {
       kEnableForkAndExitLogging : number,
       kIgnoreOtherEndpointSecurityClients : number,
       kEnableDebugLogging : number,
-      kEnableBackwardsCompatibleContentEncoding : number,
       kFCMProject : string,
       kFCMEntity : string,
       kFCMAPIKey : string,
@@ -465,10 +462,6 @@ + (NSSet *)keyPathsForValuesAffectingEnableDebugLogging {
   return [self configStateSet];
 }
 
-+ (NSSet *)keyPathsForValuesAffectingEnableBackwardsCompatibleContentEncoding {
-  return [self configStateSet];
-}
-
 + (NSSet *)keyPathsForValuesAffectingFcmProject {
   return [self configStateSet];
 }
@@ -717,17 +710,17 @@ - (NSString *)syncClientAuthCertificateIssuer {
   return self.configState[kClientAuthCertificateIssuerKey];
 }
 
-- (SNTSyncCompressionEncoding)syncClientContentEncoding {
+- (SNTSyncContentEncoding)syncClientContentEncoding {
   NSString *contentEncoding = [self.configState[kClientContentEncoding] lowercaseString];
   if ([contentEncoding isEqualToString:@"deflate"]) {
-    return SNTSyncCompressionEncodingZlib;
+    return SNTSyncContentEncodingZlib;
   } else if ([contentEncoding isEqualToString:@"gzip"]) {
-    return SNTSyncCompressionEncodingGzip;
+    return SNTSyncContentEncodingGzip;
   } else if ([contentEncoding isEqualToString:@"none"]) {
-    return SNTSyncCompressionEncodingNone;
+    return SNTSyncContentEncodingNone;
   } else {
     // Ensure we have the same default zlib behavior Santa's always had otherwise.
-    return SNTSyncCompressionEncodingZlib;
+    return SNTSyncContentEncodingZlib;
   }
 }
 
@@ -904,11 +897,6 @@ - (BOOL)enableDebugLogging {
   return [number boolValue] || self.debugFlag;
 }
 
-- (BOOL)enableBackwardsCompatibleContentEncoding {
-  NSNumber *number = self.configState[kEnableBackwardsCompatibleContentEncoding];
-  return number ? [number boolValue] : NO;
-}
-
 - (NSString *)fcmProject {
   return self.configState[kFCMProject];
 }

Source/santasyncservice/SNTSyncManager.m

@@ -391,11 +391,7 @@ - (SNTSyncState *)createSyncStateWithStatus:(SNTSyncStatusType *)status {
 
   syncState.session = [authURLSession session];
   syncState.daemonConn = self.daemonConn;
-  syncState.compressionEncoding = config.syncClientContentEncoding;
-
-  syncState.compressedContentEncoding =
-    config.enableBackwardsCompatibleContentEncoding ? @"zlib" : @"deflate";
-
+  syncState.contentEncoding = config.syncClientContentEncoding;
   syncState.pushNotificationsToken = self.pushNotifications.token;
 
   return syncState;

Source/santasyncservice/SNTSyncStage.m

@@ -74,19 +74,19 @@ - (NSMutableURLRequest *)requestWithDictionary:(NSDictionary *)dictionary {
   NSData *compressed;
   NSString *contentEncodingHeader;
 
-  switch (self.syncState.compressionEncoding) {
-    case SNTSyncCompressionEncodingNone: break;
-    case SNTSyncCompressionEncodingGzip:
+  switch (self.syncState.contentEncoding) {
+    case SNTSyncContentEncodingNone: break;
+    case SNTSyncContentEncodingGzip:
       compressed = [requestBody gzipCompressed];
       contentEncodingHeader = @"gzip";
       break;
-    case SNTSyncCompressionEncodingZlib:
+    case SNTSyncContentEncodingZlib:
       compressed = [requestBody zlibCompressed];
       contentEncodingHeader = @"deflate";
       break;
     default:
-      compressed = [requestBody zlibCompressed];
-      contentEncodingHeader = self.syncState.compressedContentEncoding;
+      // This would be a programming error.
+      LOGD(@"Unexpected value for content encoding %ld", self.syncState.contentEncoding);
   }
 
   if (compressed) {

Source/santasyncservice/SNTSyncState.h

@@ -74,11 +74,7 @@
 /// Array of bundle IDs to find binaries for.
 @property NSArray *bundleBinaryRequests;
 
-/// The header value for ContentEncoding when sending compressed content.
-/// Either "deflate" (default) or "zlib".
-@property(copy) NSString *compressedContentEncoding;
-
-/// The compression type to use for the sync session.
-@property SNTSyncCompressionEncoding compressionEncoding;
+/// The content-encoding to use for the client uploads during the sync session.
+@property SNTSyncContentEncoding contentEncoding;
 
 @end