Make Database initialization more Swift-like

Carrying over ":memory:" and "" seems less-than-ideal.

Signed-off-by: Stephen Celis <stephen@stephencelis.com>

Author: stephencelis

SQLite Tests/DatabaseTests.swift

@@ -9,6 +9,32 @@ class DatabaseTests: SQLiteTestCase {
         createUsersTable()
     }
 
+    func test_init_withInMemory_returnsInMemoryConnection() {
+        let db = Database(.InMemory)
+        XCTAssertEqual("", db.description)
+        XCTAssertEqual(":memory:", Database.Location.InMemory.description)
+    }
+
+    func test_init_returnsInMemoryByDefault() {
+        let db = Database()
+        XCTAssertEqual("", db.description)
+    }
+
+    func test_init_withTemporary_returnsTemporaryConnection() {
+        let db = Database(.Temporary)
+        XCTAssertEqual("", db.description)
+    }
+
+    func test_init_withURI_returnsURIConnection() {
+        let db = Database(.URI("\(NSTemporaryDirectory())/SQLite.swift Tests.sqlite3"))
+        XCTAssertEqual("\(NSTemporaryDirectory())/SQLite.swift Tests.sqlite3", db.description)
+    }
+
+    func test_init_withString_returnsURIConnection() {
+        let db = Database("\(NSTemporaryDirectory())/SQLite.swift Tests.sqlite3")
+        XCTAssertEqual("\(NSTemporaryDirectory())/SQLite.swift Tests.sqlite3", db.description)
+    }
+
     func test_readonly_returnsFalseOnReadWriteConnections() {
         XCTAssert(!db.readonly)
     }

SQLite/Database.swift

@@ -27,26 +27,64 @@ import sqlite3
 /// A connection (handle) to SQLite.
 public final class Database {
 
+    /// The location of a SQLite database.
+    public enum Location {
+
+        /// An in-memory database (equivalent to `.URI(":memory:")`).
+        ///
+        /// See: <https://www.sqlite.org/inmemorydb.html#sharedmemdb>
+        case InMemory
+
+        /// A temporary, file-backed database (equivalent to `.URI("")`).
+        ///
+        /// See: <https://www.sqlite.org/inmemorydb.html#temp_db>
+        case Temporary
+
+        /// A database located at the given URI filename (or path).
+        ///
+        /// See: <https://www.sqlite.org/uri.html>
+        ///
+        /// :param: filename A URI filename
+        case URI(String)
+
+    }
+
     internal var handle: COpaquePointer = nil
 
     /// Whether or not the database was opened in a read-only state.
     public var readonly: Bool { return sqlite3_db_readonly(handle, nil) == 1 }
 
-    /// Instantiates a new connection to a database.
+    /// Initializes a new connection to a database.
     ///
-    /// :param: path     The path to the database. Creates a new database if it
-    ///                  doesn’t already exist (unless in read-only mode). Pass
-    ///                  ":memory:" (or nothing) to open a new, in-memory
-    ///                  database. Pass "" (or nil) to open a temporary,
-    ///                  file-backed database. Default: ":memory:".
+    /// :param: location The location of the database. Creates a new database if
+    ///                  it doesn’t already exist (unless in read-only mode).
+    ///
+    ///                  Default: `.InMemory`.
     ///
     /// :param: readonly Whether or not to open the database in a read-only
-    ///                  state. Default: false.
+    ///                  state.
+    ///
+    ///                  Default: `false`.
     ///
     /// :returns: A new database connection.
-    public init(_ path: String? = ":memory:", readonly: Bool = false) {
+    public init(_ location: Location = .InMemory, readonly: Bool = false) {
         let flags = readonly ? SQLITE_OPEN_READONLY : SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE
-        try { sqlite3_open_v2(path ?? "", &self.handle, flags | SQLITE_OPEN_FULLMUTEX, nil) }
+        try { sqlite3_open_v2(location.description, &self.handle, flags | SQLITE_OPEN_FULLMUTEX, nil) }
+    }
+
+    /// Initializes a new connection to a database.
+    ///
+    /// :param: filename The location of the database. Creates a new database if
+    ///                  it doesn’t already exist (unless in read-only mode).
+    ///
+    /// :param: readonly Whether or not to open the database in a read-only
+    ///                  state.
+    ///
+    ///                  Default: `false`.
+    ///
+    /// :returns: A new database connection.
+    public convenience init(_ filename: String, readonly: Bool = false) {
+        self.init(.URI(filename), readonly: readonly)
     }
 
     deinit { try { sqlite3_close(self.handle) } } // sqlite3_close_v2 in Yosemite/iOS 8?
@@ -583,6 +621,21 @@ extension Database: Printable {
 
 }
 
+extension Database.Location: Printable {
+
+    public var description: String {
+        switch self {
+        case .InMemory:
+            return ":memory:"
+        case .Temporary:
+            return ""
+        case .URI(let URI):
+            return URI
+        }
+    }
+
+}
+
 internal func quote(#literal: String) -> String {
     return quote(literal, "'")
 }