Adding Multi-Resource support to the Firebase iOS SDK (#278)

* Adding Multi-Resource support to the Firebase iOS SDK.

This CL also makes RepoInfo hashable and simplifies RepoManager based on this.

5 files changed, 142 insertions, 54 deletions

diff --git a/Firebase/Database/Api/FIRDatabase.m b/Firebase/Database/Api/FIRDatabase.m
index 2dd77f6..4a8f5b8 100644
--- a/Firebase/Database/Api/FIRDatabase.m
+++ b/Firebase/Database/Api/FIRDatabase.m
@@ -36,6 +36,9 @@
 
 @implementation FIRDatabase
 
+/** A NSMutableDictionary of FirebaseApp name and FRepoInfo to FirebaseDatabase instance. */
+typedef NSMutableDictionary<NSString *, NSMutableDictionary<FRepoInfo *, FIRDatabase *> *> FIRDatabaseDictionary;
+
 // The STR and STR_EXPAND macro allow a numeric version passed to he compiler driver
 // with a -D to be treated as a string instead of an invalid floating point value.
 #define STR(x) STR_EXPAND(x)
@@ -51,13 +54,15 @@ static const char *FIREBASE_SEMVER = (const char *)STR(FIRDatabase_VERSION);
       NSString *appName = note.userInfo[kFIRAppNameKey];
       if (appName == nil) { return; }
 
-      NSMutableDictionary *instances = [self instances];
+      FIRDatabaseDictionary* instances = [self instances];
       @synchronized (instances) {
-          FIRDatabase *deletedApp = instances[appName];
-          if (deletedApp) {
+          NSMutableDictionary<FRepoInfo *, FIRDatabase *> *databaseInstances = instances[appName];
+          if (databaseInstances) {
               // Clean up the deleted instance in an effort to remove any resources still in use.
               // Note: Any leftover instances of this exact database will be invalid.
-              [FRepoManager disposeRepos:deletedApp.config];
+              for (FIRDatabase * database in [databaseInstances allValues]) {
+                  [FRepoManager disposeRepos:database.config];
+              }
               [instances removeObjectForKey:appName];
           }
       }
@@ -65,16 +70,18 @@ static const char *FIREBASE_SEMVER = (const char *)STR(FIRDatabase_VERSION);
 }
 
 /**
- * A static NSMutableDictionary of FirebaseApp names to FirebaseDatabase instance. To ensure thread-
- * safety, it should only be accessed in databaseForApp, which is synchronized.
+ * A static NSMutableDictionary of FirebaseApp name and FRepoInfo to
+ * FirebaseDatabase instance. To ensure thread-safety, it should only be
+ * accessed in databaseForApp:URL:, which is synchronized.
  *
  * TODO: This serves a duplicate purpose as RepoManager.  We should clean up.
- * TODO: We should maybe be conscious of leaks and make this a weak map or similar
- * but we have a lot of work to do to allow FirebaseDatabase/Repo etc. to be GC'd.
+ * TODO: We should maybe be conscious of leaks and make this a weak map or
+ * similar but we have a lot of work to do to allow FirebaseDatabase/Repo etc.
+ * to be GC'd.
  */
-+ (NSMutableDictionary *)instances {
++ (FIRDatabaseDictionary *)instances {
     static dispatch_once_t pred = 0;
-    static NSMutableDictionary *instances;
+    static FIRDatabaseDictionary *instances;
     dispatch_once(&pred, ^{
         instances = [NSMutableDictionary dictionary];
     });
@@ -92,27 +99,59 @@ static const char *FIREBASE_SEMVER = (const char *)STR(FIRDatabase_VERSION);
     return [FIRDatabase databaseForApp:app];
 }
 
++ (FIRDatabase *)databaseWithURL:(NSString *)url {
+    FIRApp *app = [FIRApp defaultApp];
+    if (app == nil) {
+        [NSException raise:@"FIRAppNotConfigured"
+                    format:@"Failed to get default Firebase Database instance. "
+                           @"Must call `[FIRApp configure]` (`FirebaseApp.configure()` in Swift) "
+                           @"before using Firebase Database."];
+    }
+    return [FIRDatabase databaseForApp:app URL:url];
+}
+
 + (FIRDatabase *)databaseForApp:(FIRApp *)app {
     if (app == nil) {
         [NSException raise:@"InvalidFIRApp" format:@"nil FIRApp instance passed to databaseForApp."];
     }
-    NSMutableDictionary *instances = [self instances];
-    @synchronized (instances) {
-        FIRDatabase *database = instances[app.name];
-        if (!database) {
-            NSString *databaseUrl = app.options.databaseURL;
-            if (databaseUrl == nil) {
-                [NSException raise:@"MissingDatabaseURL" format:@"Failed to get FIRDatabase instance: FIRApp object has no "
-                        "databaseURL in its FirebaseOptions object."];
-            }
 
-            FParsedUrl *parsedUrl = [FUtilities parseUrl:databaseUrl];
-            if (![parsedUrl.path isEmpty]) {
-                [NSException raise:@"InvalidDatabaseURL" format:@"Configured Database URL '%@' is invalid. It should "
-                                                                        "point to the root of a Firebase Database but it includes a path: %@",
-                                                                databaseUrl, [parsedUrl.path toString]];
-            }
+    return [FIRDatabase databaseForApp:app URL:app.options.databaseURL];
+}
 
++ (FIRDatabase *)databaseForApp:(FIRApp *)app URL:(NSString *)url {
+    if (app == nil) {
+        [NSException raise:@"InvalidFIRApp"
+                    format:@"nil FIRApp instance passed to databaseForApp."];
+    }
+
+    if (url == nil) {
+        [NSException raise:@"MissingDatabaseURL"
+                    format:@"Failed to get FirebaseDatabase instance: "
+                            "Specify DatabaseURL within FIRApp or from your databaseForApp:URL: call."];
+    }
+
+    NSURL *databaseUrl = [NSURL URLWithString:url];
+
+    if (databaseUrl == nil) {
+        [NSException raise:@"InvalidDatabaseURL" format:@"The Database URL '%@' cannot be parsed. "
+            "Specify a valid DatabaseURL within FIRApp or from your databaseForApp:URL: call.", databaseUrl];
+    } else if (![databaseUrl.path isEqualToString:@""] && ![databaseUrl.path isEqualToString:@"/"]) {
+        [NSException raise:@"InvalidDatabaseURL" format:@"Configured Database URL '%@' is invalid. It should point "
+            "to the root of a Firebase Database but it includes a path: %@",databaseUrl, databaseUrl.path];
+  }
+
+    FIRDatabaseDictionary *instances = [self instances];
+    @synchronized (instances) {
+        NSMutableDictionary<FRepoInfo *, FIRDatabase *> *urlInstanceMap =
+            instances[app.name];
+        if (!urlInstanceMap) {
+            urlInstanceMap = [NSMutableDictionary dictionary];
+            instances[app.name] = urlInstanceMap;
+        }
+
+        FParsedUrl *parsedUrl = [FUtilities parseUrl:databaseUrl.absoluteString];
+        FIRDatabase *database = urlInstanceMap[parsedUrl.repoInfo];
+        if (!database) {
             id<FAuthTokenProvider> authTokenProvider = [FAuthTokenProvider authTokenProviderForApp:app];
 
             // If this is the default app, don't set the session persistence key so that we use our
@@ -125,8 +164,10 @@ static const char *FIREBASE_SEMVER = (const char *)STR(FIRDatabase_VERSION);
 
             FIRDatabaseConfig *config = [[FIRDatabaseConfig alloc] initWithSessionIdentifier:sessionIdentifier
                                                                            authTokenProvider:authTokenProvider];
-            database = [[FIRDatabase alloc] initWithApp:app repoInfo:parsedUrl.repoInfo config:config];
-            instances[app.name] = database;
+            database = [[FIRDatabase alloc] initWithApp:app
+                                               repoInfo:parsedUrl.repoInfo
+                                                 config:config];
+            urlInstanceMap[parsedUrl.repoInfo] = database;
         }
 
         return database;
diff --git a/Firebase/Database/Core/FRepoInfo.h b/Firebase/Database/Core/FRepoInfo.h
index dace937..433bf35 100644
--- a/Firebase/Database/Core/FRepoInfo.h
+++ b/Firebase/Database/Core/FRepoInfo.h
@@ -16,7 +16,7 @@
 
 #import <Foundation/Foundation.h>
 
-@interface FRepoInfo : NSObject
+@interface FRepoInfo : NSObject <NSCopying>
 
 @property (nonatomic, readonly, strong) NSString* host;
 @property (nonatomic, readonly, strong) NSString* namespace;
@@ -31,4 +31,8 @@
 - (BOOL) isDemoHost;
 - (BOOL) isCustomHost;
 
+- (id)copyWithZone:(NSZone *)zone;
+- (NSUInteger)hash;
+- (BOOL)isEqual:(id)anObject;
+
 @end
diff --git a/Firebase/Database/Core/FRepoInfo.m b/Firebase/Database/Core/FRepoInfo.m
index 6b15fe5..925163e 100644
--- a/Firebase/Database/Core/FRepoInfo.m
+++ b/Firebase/Database/Core/FRepoInfo.m
@@ -112,4 +112,23 @@
     return url;
 }
 
+- (id)copyWithZone:(NSZone *)zone; {
+    return self; // Immutable
+}
+
+- (NSUInteger)hash {
+    NSUInteger result = host.hash;
+    result = 31 * result + (secure ? 1 : 0);
+    result = 31 * result + namespace.hash;
+    result = 31 * result + host.hash;
+    return result;
+}
+
+- (BOOL)isEqual:(id)anObject {
+    if (![anObject isKindOfClass:[FRepoInfo class]]) return NO;
+    FRepoInfo *other = (FRepoInfo *)anObject;
+    return secure == other.secure && [host isEqualToString:other.host] &&
+           [namespace isEqualToString:other.namespace];
+}
+
 @end
diff --git a/Firebase/Database/Core/FRepoManager.m b/Firebase/Database/Core/FRepoManager.m
index 6a134d2..c5194d5 100644
--- a/Firebase/Database/Core/FRepoManager.m
+++ b/Firebase/Database/Core/FRepoManager.m
@@ -24,9 +24,13 @@
 
 @implementation FRepoManager
 
-+ (NSMutableDictionary *)configs {
+typedef NSMutableDictionary<NSString *,
+                            NSMutableDictionary<FRepoInfo *, FRepo *> *>
+    FRepoDictionary;
+
++ (FRepoDictionary *)configs {
     static dispatch_once_t pred = 0;
-    static NSMutableDictionary *configs;
+    static FRepoDictionary *configs;
     dispatch_once(&pred, ^{
         configs = [NSMutableDictionary dictionary];
     });
@@ -39,33 +43,32 @@
  */
 + (FRepo *) getRepo:(FRepoInfo *)repoInfo config:(FIRDatabaseConfig *)config {
     [config freeze];
-    NSString* repoHashString = [NSString stringWithFormat:@"%@_%@", repoInfo.host, repoInfo.namespace];
-    NSMutableDictionary *configs = [FRepoManager configs];
+    FRepoDictionary *configs = [FRepoManager configs];
     @synchronized(configs) {
-        NSMutableDictionary *repos = configs[config.sessionIdentifier];
-        if (!repos || repos[repoHashString] == nil) {
+        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
+        if (!repos || repos[repoInfo] == nil) {
             // Calling this should create the repo.
             [FIRDatabase createDatabaseForTests:repoInfo config:config];
         }
 
-        return configs[config.sessionIdentifier][repoHashString];
+        return configs[config.sessionIdentifier][repoInfo];
     }
 }
 
 + (FRepo *) createRepo:(FRepoInfo *)repoInfo config:(FIRDatabaseConfig *)config database:(FIRDatabase *)database {
     [config freeze];
-    NSString* repoHashString = [NSString stringWithFormat:@"%@_%@", repoInfo.host, repoInfo.namespace];
-    NSMutableDictionary *configs = [FRepoManager configs];
+    FRepoDictionary *configs = [FRepoManager configs];
     @synchronized(configs) {
-        NSMutableDictionary *repos = configs[config.sessionIdentifier];
+        NSMutableDictionary<FRepoInfo *, FRepo *> *repos =
+            configs[config.sessionIdentifier];
         if (!repos) {
             repos = [NSMutableDictionary dictionary];
             configs[config.sessionIdentifier] = repos;
         }
-        FRepo *repo = repos[repoHashString];
+        FRepo *repo = repos[repoInfo];
         if (repo == nil) {
             repo = [[FRepo alloc] initWithRepoInfo:repoInfo config:config database:database];
-            repos[repoHashString] = repo;
+            repos[repoInfo] = repo;
             return repo;
         } else {
             [NSException raise:@"RepoExists" format:@"createRepo called for Repo that already exists."];
@@ -76,9 +79,9 @@
 
 + (void) interrupt:(FIRDatabaseConfig *)config {
     dispatch_async([FIRDatabaseQuery sharedQueue], ^{
-        NSMutableDictionary *configs = [FRepoManager configs];
-        NSMutableDictionary *repos = configs[config.sessionIdentifier];
-        for (FRepo* repo in [repos allValues]) {
+        FRepoDictionary *configs = [FRepoManager configs];
+        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
+        for (FRepo *repo in [repos allValues]) {
             [repo interrupt];
         }
     });
@@ -86,20 +89,20 @@
 
 + (void) interruptAll {
     dispatch_async([FIRDatabaseQuery sharedQueue], ^{
-        NSMutableDictionary *configs = [FRepoManager configs];
-        for (NSMutableDictionary *repos in [configs allValues]) {
-            for (FRepo* repo in [repos allValues]) {
-                [repo interrupt];
-            }
+        FRepoDictionary *configs = [FRepoManager configs];
+        for (NSMutableDictionary<FRepoInfo *, FRepo *> *repos in [configs allValues]) {
+              for (FRepo *repo in [repos allValues]) {
+                    [repo interrupt];
+              }
         }
     });
 }
 
 + (void) resume:(FIRDatabaseConfig *)config {
     dispatch_async([FIRDatabaseQuery sharedQueue], ^{
-        NSMutableDictionary *configs = [FRepoManager configs];
-        NSMutableDictionary *repos = configs[config.sessionIdentifier];
-        for (FRepo* repo in [repos allValues]) {
+        FRepoDictionary *configs = [FRepoManager configs];
+        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
+        for (FRepo *repo in [repos allValues]) {
             [repo resume];
         }
     });
@@ -107,9 +110,9 @@
 
 + (void) resumeAll {
     dispatch_async([FIRDatabaseQuery sharedQueue], ^{
-        NSMutableDictionary *configs = [FRepoManager configs];
-        for (NSMutableDictionary *repos in [configs allValues]) {
-            for (FRepo* repo in [repos allValues]) {
+        FRepoDictionary *configs = [FRepoManager configs];
+        for (NSMutableDictionary<FRepoInfo *, FRepo *> *repos in [configs allValues]) {
+            for (FRepo *repo in [repos allValues]) {
                 [repo resume];
             }
         }
diff --git a/Firebase/Database/Public/FIRDatabase.h b/Firebase/Database/Public/FIRDatabase.h
index a67f96d..606f164 100644
--- a/Firebase/Database/Public/FIRDatabase.h
+++ b/Firebase/Database/Public/FIRDatabase.h
@@ -46,6 +46,27 @@ FIR_SWIFT_NAME(Database)
 + (FIRDatabase *) database FIR_SWIFT_NAME(database());
 
 /**
+ * Gets a FirebaseDatabase instance for the specified URL.
+ *
+ * @param url The URL to the Firebase Database instance you want to access.
+ * @return A FIRDatabase instance.
+ */
++ (FIRDatabase *)databaseWithURL:(NSString *)url NS_SWIFT_NAME(database(url:));
+
+/**
+ * Gets a FirebaseDatabase instance for the specified URL, using the specified
+ * FirebaseApp.
+ *
+ * @param app The FIRApp to get a FIRDatabase for.
+ * @param url The URL to the Firebase Database instance you want to access.
+ * @return A FIRDatabase instance.
+ */
+// clang-format off
++ (FIRDatabase *)databaseForApp:(FIRApp *)app
+                            URL:(NSString *)url NS_SWIFT_NAME(database(app:url:));
+// clang-format on
+
+/**
  * Gets an instance of FIRDatabase for a specific FIRApp.
  *
  * @param app The FIRApp to get a FIRDatabase for.