Fleshing out some more of the queue

FMDBSwift/Sources/FMDB/FMDatabase.swift

@@ -35,7 +35,7 @@ public class FMDatabase : NSObject {
   
     private var _db : OpaquePointer?
     var _databasePath : String?
-    private var _isOpen : Bool
+    internal var _isOpen : Bool
     private var _maxBusyRetryTimeInterval : TimeInterval = 2
     private var _startBusyRetryTime : TimeInterval = 0
     public var logsErrors : Bool
@@ -207,7 +207,7 @@ public class FMDatabase : NSObject {
     }
     
     
-    public func openWithFlags(flags : Int32, vfsName : String?) throws -> Bool {
+    @discardableResult public func openWithFlags(flags : Int32, vfsName : String?) throws -> Bool {
         
         if (_isOpen) {
             return true
@@ -823,7 +823,7 @@ public class FMDatabase : NSObject {
         _isInTransaction
     }
 
-    func interrupt() -> Bool {
+    @discardableResult func interrupt() -> Bool {
         if (_db != nil) {
             sqlite3_interrupt(_db);
             return true;

FMDBSwift/Sources/FMDB/FMDatabaseQueue.swift

@@ -4,4 +4,256 @@ import SQLite3
 public class FMDatabaseQueue : NSObject {
     
     
+    enum FMDBTransaction : Int32 {
+        case FMDBTransactionExclusive = 1,
+             FMDBTransactionDeferred  = 2,
+             FMDBTransactionImmediate = 3
+    }
+    
+    
+    
+    var _databasePath : String?
+    var _openFlags : Int32 = SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE
+    var _vfsName : String?
+    private var _db : FMDatabase?
+    
+    static var savePointIdx : CUnsignedLong = 0
+    
+    public let queue = DispatchQueue(label: "fmdb.\(String(describing: self))")
+    
+    private let queueKey = DispatchSpecificKey<FMDatabaseQueue>()
+    
+    public override init() {
+        super.init()
+        
+        queue.setSpecific(key:queueKey, value:self)
+        
+        print(queue)
+    }
+    
+    deinit {
+        
+        if let _db = _db {
+            queue.sync {
+                if (!_db.close()) {
+                    print("Could not close database")
+                }
+            }
+        }
+        
+        
+    }
+    
+    public func interrupt() {
+        _db?.interrupt()
+    }
+    
+    // FIXME: What would the swift version of this be?
+    /*
+     + (Class)databaseClass {
+         return [FMDatabase class];
+     }
+     */
+    
+    
+    
+    
+    
+    
+    static func queue(with filePath : String) -> FMDatabaseQueue {
+        
+        let q = FMDatabaseQueue()
+        
+        q._databasePath = filePath
+        
+        return q
+    }
+    
+    static func queue(with fileURL : URL) -> FMDatabaseQueue {
+        return FMDatabaseQueue.queue(with: fileURL.path)
+    }
+    
+    func database() -> FMDatabase? {
+        
+        if (_db == nil || !(_db!._isOpen)) {
+            
+            if (_db == nil) {
+                
+                _db = FMDatabase.database(with: _databasePath!)
+                
+            }
+            
+            do {
+                try _db?.openWithFlags(flags: _openFlags, vfsName: _vfsName)
+            }
+            catch {
+                print(error)
+                abort()
+            }
+        }
+        
+        return _db
+        
+    }
+    
+    func inDatabase(_ f: (FMDatabase) -> ()) {
+      
+        /* Get the currently executing queue (which should probably be nil, but in theory could be another DB queue
+         * and then check it against self to make sure we're not about to deadlock. */
+        
+        let currentSyncQueue = queue.getSpecific(key: queueKey)
+        assert(currentSyncQueue != self, "inDatabase: was called reentrantly on the same queue, which would lead to a deadlock")
+
+        
+        queue.sync {
+            
+            let db = database()
+            
+            f(db!)
+            
+            
+            if (db!.hasOpenResultSets()) {
+                print("Warning: there is at least one open result set around after performing FMDatabaseQueue.inDatabase()")
+            }
+        }
+    }
+    
+    
+    func beginTransaction(transaction: FMDBTransaction, f: (FMDatabase, inout Bool) -> ()) {
+        
+        
+        queue.sync {
+            
+            if let db = database() {
+                
+                var shouldRollback = false
+                
+                do {
+                    
+                    switch (transaction) {
+                        
+                    case .FMDBTransactionExclusive:
+                        try db.beginExclusiveTransaction()
+                        break
+                             
+                    case .FMDBTransactionDeferred:
+                        try db.beginDeferredTransaction()
+                        break
+                        
+                    case .FMDBTransactionImmediate:
+                        try db.beginImmediateTransaction()
+                        break
+                        
+                    }
+                    
+                    f(db, &shouldRollback)
+                    
+                    if (shouldRollback) {
+                        try db.rollback();
+                    }
+                    else {
+                        try db.commit();
+                    }
+                }
+                catch {
+                    print(error)
+                }
+            }
+        }
+        
+    }
+    
+    
+    func inTransaction(_ f: (FMDatabase, inout Bool) -> ()) {
+        beginTransaction(transaction: .FMDBTransactionExclusive, f: f)
+    }
+    
+    func inDeferredTransaction(_ f: (FMDatabase, inout Bool) -> ()) {
+        beginTransaction(transaction: .FMDBTransactionDeferred, f: f)
+    }
+    
+    func inExclusiveTransaction(_ f: (FMDatabase, inout Bool) -> ()) {
+        beginTransaction(transaction: .FMDBTransactionExclusive, f: f)
+    }
+    
+    func inImmediateTransaction(_ f: (FMDatabase, inout Bool) -> ()) {
+        beginTransaction(transaction: .FMDBTransactionImmediate, f: f)
+    }
+    
+    
+    func inSavePoint(_ f: (FMDatabase, inout Bool) -> ()) {
+        
+        
+        queue.sync {
+            
+            #warning("Need to implement startSavePointWithName in FMDatabase before the Queue can do inSavePoint:")
+            FMDatabaseQueue.savePointIdx = FMDatabaseQueue.savePointIdx + 1
+            
+//            let name = "savePoint\(FMDatabaseQueue.savePointIdx)"
+//            var shouldRollback = false
+//
+        }
+        
+    }
+    
+    
+    /*
+     
+     - (NSError*)inSavePoint:(__attribute__((noescape)) void (^)(FMDatabase *db, BOOL *rollback))block {
+     #if SQLITE_VERSION_NUMBER >= 3007000
+         static unsigned long savePointIdx = 0;
+         __block NSError *err = 0x00;
+         FMDBRetain(self);
+         dispatch_sync(_queue, ^() {
+             
+             NSString *name = [NSString stringWithFormat:@"savePoint%ld", savePointIdx++];
+             
+             BOOL shouldRollback = NO;
+             
+             if ([[self database] startSavePointWithName:name error:&err]) {
+                 
+                 block([self database], &shouldRollback);
+                 
+                 if (shouldRollback) {
+                     // We need to rollback and release this savepoint to remove it
+                     [[self database] rollbackToSavePointWithName:name error:&err];
+                 }
+                 [[self database] releaseSavePointWithName:name error:&err];
+                 
+             }
+         });
+         FMDBRelease(self);
+         return err;
+     #else
+         NSString *errorMessage = NSLocalizedStringFromTable(@"Save point functions require SQLite 3.7", @"FMDB", nil);
+         if (_db.logsErrors) NSLog(@"%@", errorMessage);
+         return [NSError errorWithDomain:@"FMDatabase" code:0 userInfo:@{NSLocalizedDescriptionKey : errorMessage}];
+     #endif
+     }
+
+     - (BOOL)checkpoint:(FMDBCheckpointMode)mode error:(NSError * __autoreleasing *)error
+     {
+         return [self checkpoint:mode name:nil logFrameCount:NULL checkpointCount:NULL error:error];
+     }
+
+     - (BOOL)checkpoint:(FMDBCheckpointMode)mode name:(NSString *)name error:(NSError * __autoreleasing *)error
+     {
+         return [self checkpoint:mode name:name logFrameCount:NULL checkpointCount:NULL error:error];
+     }
+
+     - (BOOL)checkpoint:(FMDBCheckpointMode)mode name:(NSString *)name logFrameCount:(int * _Nullable)logFrameCount checkpointCount:(int * _Nullable)checkpointCount error:(NSError * __autoreleasing _Nullable * _Nullable)error
+     {
+         __block BOOL result;
+
+         FMDBRetain(self);
+         dispatch_sync(_queue, ^() {
+             result = [self.database checkpoint:mode name:name logFrameCount:logFrameCount checkpointCount:checkpointCount error:error];
+         });
+         FMDBRelease(self);
+         
+         return result;
+     }
+
+     */
+    
 }

FMDBSwift/Tests/FMDBTests/FMDatabaseQueueTests.swift

@@ -0,0 +1,57 @@
+import XCTest
+import SQLite3
+@testable import FMDB
+
+final class FMDatabaseQueueTests: FMDBTempDBTests {
+    
+    let tempPath = "/tmp/FMDatabaseQueueTests.db"
+    
+    override func setUp() {
+        
+    }
+    
+    /*
+    func testURLOpenNoPath() throws {
+        
+        do {
+            let q = FMDatabaseQueue()
+            XCTAssert(q != nil, "Database queue should be returned")
+        }
+        
+        catch {
+            print(error)
+            XCTAssert(false)
+        }
+    }*/
+    
+    func testSimpleSelect() throws {
+        
+        let q = FMDatabaseQueue.queue(with: tempPath)
+        
+        var worked = false
+        
+        q.inDatabase({ db in
+            
+            do {
+                let rs = try db.executeQuery("select 'hello'")
+                try rs.next()
+                
+                XCTAssertTrue(rs.string(0) == "hello")
+                rs.close()
+                worked = true
+            }
+            
+            catch {
+                print(error)
+                XCTAssert(false)
+            }
+            
+        })
+        
+        XCTAssert(worked)
+    }
+    
+    
+    
+    
+}