Add VACUUM support (#19)

Author: atdrendel

Sources/SQLite/Database.swift

@@ -238,6 +238,54 @@ extension Database {
     }
 }
 
+extension Database {
+    public enum AutoVacuumMode: Int {
+        case none = 0
+        case incremental = 2
+        case full = 1
+
+        fileprivate init?(_ rawValue: Int?) {
+            switch rawValue {
+            case .some(0): self = .none
+            case .some(2): self = .incremental
+            case .some(1): self = .full
+            default: return nil
+            }
+        }
+    }
+
+    public var autoVacuumMode: AutoVacuumMode {
+        get {
+            do {
+                guard let result = try execute(raw: "PRAGMA auto_vacuum;").first
+                else { return .none }
+                return AutoVacuumMode(result["auto_vacuum"]?.intValue) ?? .none
+            } catch {
+                assertionFailure("Could not get auto_vacuum: \(error))")
+                return .none
+            }
+        }
+        set {
+            do { try execute(raw: "PRAGMA auto_vacuum = \(newValue.rawValue);") }
+            catch { assertionFailure("Could not set auto_vacuum to \(newValue): \(error)") }
+        }
+    }
+
+    public func incrementalVacuum(_ pages: Int? = nil) throws {
+        let sql: SQL
+        if let pages = pages {
+            sql = "PRAGMA incremental_vacuum(\(pages));"
+        } else {
+            sql = "PRAGMA incremental_vacuum;"
+        }
+        try execute(raw: sql)
+    }
+
+    public func vacuum() throws {
+        try execute(raw: "VACUUM;")
+    }
+}
+
 extension Database {
     func createUpdateHandler(_ block: @escaping (String) -> Void) {
         let updateBlock: UpdateHookCallback = { _, _, _, tableName, _ in

Tests/SQLiteTests/DatabaseTests.swift

@@ -38,6 +38,108 @@ class DatabaseTests: XCTestCase {
         XCTAssertTrue(database.supportsJSON)
     }
 
+    func testAutoVacuumMode() throws {
+        XCTAssertEqual(.none, database.autoVacuumMode)
+
+        database.autoVacuumMode = .full
+        XCTAssertEqual(.full, database.autoVacuumMode)
+
+        database.autoVacuumMode = .incremental
+        XCTAssertEqual(.incremental, database.autoVacuumMode)
+    }
+
+    func testIncrementalVacuumDoesNotThrowIfModeIsNotIncremental() throws {
+        XCTAssertEqual(.none, database.autoVacuumMode)
+        try database.incrementalVacuum()
+    }
+
+    func testIncrementalVacuum() throws {
+        func getPageCount() throws -> Int {
+            let result = try database.execute(raw: "PRAGMA page_count;").first
+            return try XCTUnwrap(result?["page_count"]?.intValue)
+        }
+
+        database.autoVacuumMode = .incremental
+
+        XCTAssertEqual(1, try getPageCount())
+
+        try database.execute(raw: _createTableWithBlob)
+
+        try database.inTransaction { (db) -> Void in
+            try (0..<1000).forEach { (index) in
+                let args: SQLiteArguments = [
+                    "id": .integer(Int64(index)), "data": .data(_textData)
+                ]
+                try db.write(_insertIDAndData, arguments: args)
+            }
+        }
+
+        XCTAssertGreaterThan(try getPageCount(), 3)
+
+        try database.write("DELETE FROM test;", arguments: [:])
+        try database.incrementalVacuum()
+
+        XCTAssertEqual(3, try getPageCount())
+    }
+
+    func testIncrementalVacuumWithPageCount() throws {
+        func getPageCount() throws -> Int {
+            let result = try database.execute(raw: "PRAGMA page_count;").first
+            return try XCTUnwrap(result?["page_count"]?.intValue)
+        }
+
+        database.autoVacuumMode = .incremental
+
+        XCTAssertEqual(1, try getPageCount())
+
+        try database.execute(raw: _createTableWithBlob)
+
+        try database.inTransaction { (db) -> Void in
+            try (0..<1000).forEach { (index) in
+                let args: SQLiteArguments = [
+                    "id": .integer(Int64(index)), "data": .data(_textData)
+                ]
+                try db.write(_insertIDAndData, arguments: args)
+            }
+        }
+
+        let pageCount = try getPageCount()
+        XCTAssertGreaterThan(pageCount, 3)
+
+        try database.write("DELETE FROM test;", arguments: [:])
+        try database.incrementalVacuum(2)
+
+        XCTAssertEqual(pageCount - 2, try getPageCount())
+    }
+
+    func testVacuum() throws {
+        func getPageCount() throws -> Int {
+            let result = try database.execute(raw: "PRAGMA page_count;").first
+            return try XCTUnwrap(result?["page_count"]?.intValue)
+        }
+
+        XCTAssertEqual(.none, database.autoVacuumMode)
+        XCTAssertEqual(0, try getPageCount())
+
+        try database.execute(raw: _createTableWithBlob)
+
+        try database.inTransaction { (db) -> Void in
+            try (0..<1000).forEach { (index) in
+                let args: SQLiteArguments = [
+                    "id": .integer(Int64(index)), "data": .data(_textData)
+                ]
+                try db.write(_insertIDAndData, arguments: args)
+            }
+        }
+
+        XCTAssertGreaterThan(try getPageCount(), 2)
+
+        try database.write("DELETE FROM test;", arguments: [:])
+        try database.vacuum()
+
+        XCTAssertEqual(2, try getPageCount())
+    }
+
     func testCreateTable() throws {
         XCTAssertNoThrow(try database.execute(raw: _createTableWithBlob))
         let tableNames = try database.tables()