Expose a block to determine if the Realm should be compacted on launch

CHANGELOG.md

@@ -15,6 +15,8 @@ x.x.x Release notes (yyyy-MM-dd)
   background thread before dispatching to the given queue. In addition,
   synchronized Realms wait for all remote content available at the time the
   operation began to be downloaded and available locally.
+* Add `shouldCompactOnLaunch` block property when configuring a Realm to
+  determine if it should be compacted before being returned.
 * Speed up case-insensitive queries on indexed string properties.
 * Add RLMResults's collection aggregate methods to RLMArray.
 * Add support for calling the aggregate methods on unmanaged Lists.

Realm.xcodeproj/project.pbxproj

@@ -441,9 +441,12 @@
 		E86E61241D91E4E200DC2419 /* RLMTestCase.m in Sources */ = {isa = PBXBuildFile; fileRef = E81A1FC51955FE0100FDED82 /* RLMTestCase.m */; };
 		E8917598197A1B350068ACC6 /* UnicodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E8917597197A1B350068ACC6 /* UnicodeTests.m */; };
 		E8917599197A1B350068ACC6 /* UnicodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E8917597197A1B350068ACC6 /* UnicodeTests.m */; };
+		E8AE7C261EA436F800CDFF9A /* CompactionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = E8AE7C251EA436F800CDFF9A /* CompactionTests.swift */; };
 		E8BF67FC1C24D07100E591CD /* SwiftVersion.swift in Sources */ = {isa = PBXBuildFile; fileRef = E8BF67FB1C24D07100E591CD /* SwiftVersion.swift */; };
 		E8C6EAF41DD66C0C00EC1A03 /* RLMSyncUtil_Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 1A1C6E241D3FFCF70077B6E7 /* RLMSyncUtil_Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		E8C6EAF51DD66C0C00EC1A03 /* RLMSyncUtil_Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 1A1C6E241D3FFCF70077B6E7 /* RLMSyncUtil_Private.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		E8DA16F81E81210D0055141C /* CompactionTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E8DA16F71E81210D0055141C /* CompactionTests.m */; };
+		E8DA16F91E81210D0055141C /* CompactionTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E8DA16F71E81210D0055141C /* CompactionTests.m */; };
 		E8FD2E381D93345100569F10 /* keychain_helper.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1A64CA891D8763B400BC0F9B /* keychain_helper.cpp */; };
 /* End PBXBuildFile section */
 
@@ -902,10 +905,12 @@
 		E8917597197A1B350068ACC6 /* UnicodeTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = UnicodeTests.m; sourceTree = "<group>"; };
 		E891759A197A1B600068ACC6 /* SwiftUnicodeTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SwiftUnicodeTests.swift; sourceTree = "<group>"; };
 		E8951F01196C96DE00D6461C /* RLMRealm_Dynamic.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RLMRealm_Dynamic.h; sourceTree = "<group>"; };
+		E8AE7C251EA436F800CDFF9A /* CompactionTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CompactionTests.swift; sourceTree = "<group>"; };
 		E8BF67FB1C24D07100E591CD /* SwiftVersion.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SwiftVersion.swift; sourceTree = "<group>"; };
 		E8C6EAEF1DD65B8C00EC1A03 /* RLMSyncPermissionChange_Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RLMSyncPermissionChange_Private.h; sourceTree = "<group>"; };
 		E8D89B9D1955FC6D00CF2B9A /* Realm.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = Realm.h; sourceTree = "<group>"; };
 		E8D89BA31955FC6D00CF2B9A /* Tests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = Tests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
+		E8DA16F71E81210D0055141C /* CompactionTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = CompactionTests.m; sourceTree = "<group>"; };
 		E8F8D90B196CB8DD00475368 /* SwiftTestObjects.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SwiftTestObjects.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -1235,6 +1240,7 @@
 			isa = PBXGroup;
 			children = (
 				5D6610291BE98DAA0021E04F /* Supporting Files */,
+				E8AE7C251EA436F800CDFF9A /* CompactionTests.swift */,
 				5D660FFF1BE98D880021E04F /* KVOTests.swift */,
 				5D6610001BE98D880021E04F /* ListTests.swift */,
 				5D6610011BE98D880021E04F /* MigrationTests.swift */,
@@ -1310,6 +1316,7 @@
 			children = (
 				E81A1FB81955FE0100FDED82 /* ArrayPropertyTests.m */,
 				3F7556731BE95A050058BC7E /* AsyncTests.mm */,
+				E8DA16F71E81210D0055141C /* CompactionTests.m */,
 				E81A1FBA1955FE0100FDED82 /* DynamicTests.m */,
 				021A882F1AAFB5BE00EEAC84 /* EncryptionTests.mm */,
 				E81A1FBB1955FE0100FDED82 /* EnumeratorTests.m */,
@@ -2267,6 +2274,7 @@
 				5D6610211BE98D880021E04F /* RealmTests.swift in Sources */,
 				5D6610221BE98D880021E04F /* SchemaTests.swift in Sources */,
 				5D6610231BE98D880021E04F /* SortDescriptorTests.swift in Sources */,
+				E8AE7C261EA436F800CDFF9A /* CompactionTests.swift in Sources */,
 				5D6610241BE98D880021E04F /* SwiftLinkTests.swift in Sources */,
 				5D6610251BE98D880021E04F /* SwiftTestObjects.swift in Sources */,
 				5D6610261BE98D880021E04F /* SwiftUnicodeTests.swift in Sources */,
@@ -2406,6 +2414,7 @@
 				3F8DCA7719930FCB0008BD7F /* SwiftArrayTests.swift in Sources */,
 				3F8DCA7819930FCB0008BD7F /* SwiftDynamicTests.swift in Sources */,
 				3F8DCA7919930FCB0008BD7F /* SwiftLinkTests.swift in Sources */,
+				E8DA16F91E81210D0055141C /* CompactionTests.m in Sources */,
 				3F8DCA7B19930FCB0008BD7F /* SwiftObjectInterfaceTests.swift in Sources */,
 				3F8DCA7C19930FCB0008BD7F /* SwiftPropertyTypeTest.swift in Sources */,
 				3F8DCA7D19930FCB0008BD7F /* SwiftRealmTests.swift in Sources */,
@@ -2434,6 +2443,7 @@
 				3F2E66641CA0BA11004761D5 /* NotificationTests.m in Sources */,
 				3FEB383F1E70AC8800F22712 /* ObjectCreationTests.mm in Sources */,
 				E81A1FE11955FE0100FDED82 /* ObjectInterfaceTests.m in Sources */,
+				E8DA16F81E81210D0055141C /* CompactionTests.m in Sources */,
 				021A88361AAFB5CD00EEAC84 /* ObjectSchemaTests.m in Sources */,
 				E81A1FE31955FE0100FDED82 /* ObjectTests.m in Sources */,
 				5D03FB1F1E0DAFBA007D53EA /* PredicateUtilTests.mm in Sources */,

Realm/ObjectServerTests/RLMObjectServerTests.mm

@@ -1716,4 +1716,18 @@ - (void)testPermissionOfferResponseTokenNotExist {
     [token stop];
 }
 
+#pragma mark - Validation
+
+- (void)testCompactOnLaunchCannotBeSet {
+    RLMSyncUser *user = [self logInUserForCredentials:[RLMObjectServerTests basicCredentialsWithName:ACCOUNT_NAME()
+                                                                                            register:YES]
+                                               server:[RLMObjectServerTests authServerURL]];
+    RLMSyncConfiguration *syncConfig = [[RLMSyncConfiguration alloc] initWithUser:user realmURL:REALM_URL()];
+
+    RLMRealmConfiguration *configuration = [RLMRealmConfiguration defaultConfiguration];
+    configuration.syncConfiguration = syncConfig;
+    RLMAssertThrowsWithReasonMatching(configuration.shouldCompactOnLaunch = ^BOOL(NSUInteger, NSUInteger){ return NO; },
+                                      @"Cannot set `shouldCompactOnLaunch` when `syncConfiguration` is set.");
+}
+
 @end

Realm/RLMRealmConfiguration+Sync.mm

@@ -33,6 +33,9 @@ @implementation RLMRealmConfiguration (Sync)
 #pragma mark - API
 
 - (void)setSyncConfiguration:(RLMSyncConfiguration *)syncConfiguration {
+    if (self.config.should_compact_on_launch_function) {
+        @throw RLMException(@"Cannot set `syncConfiguration` when `shouldCompactOnLaunch` is set.");
+    }
     RLMSyncUser *user = syncConfiguration.user;
     if (user.state == RLMSyncUserStateError) {
         @throw RLMException(@"Cannot set a sync configuration which has an errored-out user.");

Realm/RLMRealmConfiguration.h

@@ -21,6 +21,17 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+/**
+ A block called when opening a Realm for the first time during the life
+ of a process to determine if it should be compacted before being returned
+ to the user. It is passed the total file size (data + free space) and the total
+ bytes used by data in the file.
+
+ Return `YES` to indicate that an attempt to compact the file should be made.
+ The compaction will be skipped if another process is accessing it.
+ */
+typedef BOOL (^RLMShouldCompactOnLaunchBlock)(NSUInteger totalBytes, NSUInteger bytesUsed);
+
 /**
  An `RLMRealmConfiguration` instance describes the different options used to
  create an instance of a Realm.
@@ -91,6 +102,17 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property (nonatomic) BOOL deleteRealmIfMigrationNeeded;
 
+/**
+ A block called when opening a Realm for the first time during the life
+ of a process to determine if it should be compacted before being returned
+ to the user. It is passed the total file size (data + free space) and the total
+ bytes used by data in the file.
+
+ Return `YES` to indicate that an attempt to compact the file should be made.
+ The compaction will be skipped if another process is accessing it.
+ */
+@property (nonatomic, copy, nullable) RLMShouldCompactOnLaunchBlock shouldCompactOnLaunch;
+
 /// The classes managed by the Realm.
 @property (nonatomic, copy, nullable) NSArray *objectClasses;
 

Realm/RLMRealmConfiguration.mm

@@ -35,6 +35,7 @@
     @"schemaVersion",
     @"migrationBlock",
     @"deleteRealmIfMigrationNeeded",
+    @"shouldCompactOnLaunch",
     @"dynamic",
     @"customSchema",
 };
@@ -113,6 +114,7 @@ - (instancetype)copyWithZone:(NSZone *)zone {
     configuration->_cache = _cache;
     configuration->_dynamic = _dynamic;
     configuration->_migrationBlock = _migrationBlock;
+    configuration->_shouldCompactOnLaunch = _shouldCompactOnLaunch;
     configuration->_customSchema = _customSchema;
     return configuration;
 }
@@ -207,6 +209,8 @@ - (void)setReadOnly:(BOOL)readOnly {
     if (readOnly) {
         if (self.deleteRealmIfMigrationNeeded) {
             @throw RLMException(@"Cannot set `readOnly` when `deleteRealmIfMigrationNeeded` is set.");
+        } else if (self.shouldCompactOnLaunch) {
+            @throw RLMException(@"Cannot set `readOnly` when `shouldCompactOnLaunch` is set.");
         }
         _config.schema_mode = realm::SchemaMode::ReadOnly;
     }
@@ -275,4 +279,21 @@ - (NSString *)pathOnDisk {
     return @(_config.path.c_str());
 }
 
+- (void)setShouldCompactOnLaunch:(RLMShouldCompactOnLaunchBlock)shouldCompactOnLaunch {
+    if (shouldCompactOnLaunch) {
+        if (self.readOnly) {
+            @throw RLMException(@"Cannot set `shouldCompactOnLaunch` when `readOnly` is set.");
+        } else if (_config.sync_config) {
+            @throw RLMException(@"Cannot set `shouldCompactOnLaunch` when `syncConfiguration` is set.");
+        }
+        _config.should_compact_on_launch_function = [=](size_t totalBytes, size_t usedBytes) {
+            return shouldCompactOnLaunch(totalBytes, usedBytes);
+        };
+    }
+    else {
+        _config.should_compact_on_launch_function = nullptr;
+    }
+    _shouldCompactOnLaunch = shouldCompactOnLaunch;
+}
+
 @end