Added support for casting when Codable.

SQLite.xcodeproj/project.pbxproj

@@ -202,6 +202,11 @@
 		64B8E1702B09748000545AFB /* WindowFunctionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 64B8E16F2B09748000545AFB /* WindowFunctionsTests.swift */; };
 		64B8E1712B09748000545AFB /* WindowFunctionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 64B8E16F2B09748000545AFB /* WindowFunctionsTests.swift */; };
 		64B8E1722B09748000545AFB /* WindowFunctionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 64B8E16F2B09748000545AFB /* WindowFunctionsTests.swift */; };
+		915BE7892E2BB05300360423 /* Query+Lazy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 915BE7882E2BB05300360423 /* Query+Lazy.swift */; };
+		915BE78A2E2BB05300360423 /* Query+Lazy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 915BE7882E2BB05300360423 /* Query+Lazy.swift */; };
+		915BE78B2E2BB05300360423 /* Query+Lazy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 915BE7882E2BB05300360423 /* Query+Lazy.swift */; };
+		915BE78C2E2BB05300360423 /* Query+Lazy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 915BE7882E2BB05300360423 /* Query+Lazy.swift */; };
+		915BE78D2E2BB05300360423 /* Query+Lazy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 915BE7882E2BB05300360423 /* Query+Lazy.swift */; };
 		997DF2AE287FC06D00F8DF95 /* Query+with.swift in Sources */ = {isa = PBXBuildFile; fileRef = 997DF2AD287FC06D00F8DF95 /* Query+with.swift */; };
 		997DF2AF287FC06D00F8DF95 /* Query+with.swift in Sources */ = {isa = PBXBuildFile; fileRef = 997DF2AD287FC06D00F8DF95 /* Query+with.swift */; };
 		997DF2B0287FC06D00F8DF95 /* Query+with.swift in Sources */ = {isa = PBXBuildFile; fileRef = 997DF2AD287FC06D00F8DF95 /* Query+with.swift */; };
@@ -428,6 +433,7 @@
 		49EB68C31F7B3CB400D89D40 /* Coding.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Coding.swift; sourceTree = "<group>"; };
 		64A8EE422B095FBB00F583F7 /* WindowFunctions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowFunctions.swift; sourceTree = "<group>"; };
 		64B8E16F2B09748000545AFB /* WindowFunctionsTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowFunctionsTests.swift; sourceTree = "<group>"; };
+		915BE7882E2BB05300360423 /* Query+Lazy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Query+Lazy.swift"; sourceTree = "<group>"; };
 		997DF2AD287FC06D00F8DF95 /* Query+with.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Query+with.swift"; sourceTree = "<group>"; };
 		A121AC451CA35C79005A31D1 /* SQLite.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = SQLite.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		DB58B21028FB864300F8EEA4 /* SchemaReader.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SchemaReader.swift; sourceTree = "<group>"; };
@@ -733,6 +739,7 @@
 				EE247AFD1C3F06E900AE3E12 /* CustomFunctions.swift */,
 				EE247AFE1C3F06E900AE3E12 /* Expression.swift */,
 				EE247AFF1C3F06E900AE3E12 /* Operators.swift */,
+				915BE7882E2BB05300360423 /* Query+Lazy.swift */,
 				EE247B001C3F06E900AE3E12 /* Query.swift */,
 				997DF2AD287FC06D00F8DF95 /* Query+with.swift */,
 				EE247B011C3F06E900AE3E12 /* Schema.swift */,
@@ -1133,6 +1140,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				915BE78D2E2BB05300360423 /* Query+Lazy.swift in Sources */,
 				03A65E801C6BB2FB0062603F /* CoreFunctions.swift in Sources */,
 				49EB68C61F7B3CB400D89D40 /* Coding.swift in Sources */,
 				03A65E761C6BB2E60062603F /* Blob.swift in Sources */,
@@ -1220,6 +1228,7 @@
 				49EB68C71F7B3CB400D89D40 /* Coding.swift in Sources */,
 				997DF2B1287FC06D00F8DF95 /* Query+with.swift in Sources */,
 				3D67B3F71DB246D700A4F4C6 /* Foundation.swift in Sources */,
+				915BE78C2E2BB05300360423 /* Query+Lazy.swift in Sources */,
 				3D67B3F81DB246D700A4F4C6 /* Helpers.swift in Sources */,
 				DB58B21428FB864300F8EEA4 /* SchemaReader.swift in Sources */,
 				3D67B3E91DB246D100A4F4C6 /* Statement.swift in Sources */,
@@ -1262,6 +1271,7 @@
 				DEB306BD2B61CEF500F9D46B /* Coding.swift in Sources */,
 				DEB306BE2B61CEF500F9D46B /* RTree.swift in Sources */,
 				DEB306BF2B61CEF500F9D46B /* Blob.swift in Sources */,
+				915BE7892E2BB05300360423 /* Query+Lazy.swift in Sources */,
 				DEB306C02B61CEF500F9D46B /* URIQueryParameter.swift in Sources */,
 				DEB306C12B61CEF500F9D46B /* Foundation.swift in Sources */,
 				DEB306C22B61CEF500F9D46B /* Connection.swift in Sources */,
@@ -1338,6 +1348,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				915BE78A2E2BB05300360423 /* Query+Lazy.swift in Sources */,
 				EE247B0F1C3F06E900AE3E12 /* CoreFunctions.swift in Sources */,
 				49EB68C41F7B3CB400D89D40 /* Coding.swift in Sources */,
 				EE247B0A1C3F06E900AE3E12 /* RTree.swift in Sources */,
@@ -1421,6 +1432,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				915BE78B2E2BB05300360423 /* Query+Lazy.swift in Sources */,
 				EE247B6F1C3F3FEC00AE3E12 /* CoreFunctions.swift in Sources */,
 				49EB68C51F7B3CB400D89D40 /* Coding.swift in Sources */,
 				EE247B651C3F3FEC00AE3E12 /* Blob.swift in Sources */,

Sources/SQLite/Core/Statement.swift

@@ -166,7 +166,7 @@ public final class Statement {
 
         reset(clearBindings: false)
         _ = try step()
-        return row[0]
+        return try row.getValue(0)
     }
 
     /// - Parameter bindings: A list of parameters to bind to the statement.
@@ -229,9 +229,9 @@ extension Array {
 }
 
 extension Statement: FailableIterator {
-    public typealias Element = [Binding?]
-    public func failableNext() throws -> [Binding?]? {
-        try step() ? Array(row) : nil
+    public typealias Element = Cursor
+    public func failableNext() throws -> Cursor? {
+        try step() ? row : nil
     }
 }
 
@@ -258,30 +258,103 @@ extension Statement: CustomStringConvertible {
 
 }
 
-public struct Cursor {
+public protocol CursorProtocol {
+    func getValue(_ idx: Int) throws -> Binding?
+    func getValue(_ idx: Int) throws -> Double
+    func getValue(_ idx: Int) throws -> Int64
+    func getValue(_ idx: Int) throws -> String
+    func getValue(_ idx: Int) throws -> Blob
+}
+
+extension CursorProtocol {
+    public func getValue<T: Binding>(_ idx: Int) -> T? {
+        switch T.self {
+        case is Double.Type:
+            return try? getValue(idx) as Double as? T
+        case is Int64.Type:
+            return try? getValue(idx) as Int64 as? T
+        case is String.Type:
+            return try? getValue(idx) as String as? T
+        case is Blob.Type:
+            return try? getValue(idx) as Blob as? T
+        default:
+            return nil
+        }
+    }
+
+    public func getValue(_ idx: Int) throws -> Bool {
+        try Bool.fromDatatypeValue(getValue(idx))
+    }
+
+    public func getValue(_ idx: Int) throws -> Int {
+        try Int.fromDatatypeValue(getValue(idx))
+    }
+}
+
+struct CursorWithBindingArray: CursorProtocol {
+    let elements: [Binding?]
+    init(elements: [Binding?]) {
+        self.elements = elements
+    }
+
+    func getValue(_ idx: Int) throws -> Binding? {
+        elements[idx]
+    }
+    func getValue(_ idx: Int) throws -> Double {
+        guard let value = elements[idx] as? Double else {
+            throw QueryError.unexpectedNullValue(name: "column at index \(idx)")
+        }
+        return value
+    }
+    func getValue(_ idx: Int) throws -> Int64 {
+        guard let value = elements[idx] as? Int64 else {
+            throw QueryError.unexpectedNullValue(name: "column at index \(idx)")
+        }
+        return value
+    }
+    func getValue(_ idx: Int) throws -> String {
+        guard let value = elements[idx] as? String else {
+            throw QueryError.unexpectedNullValue(name: "column at index \(idx)")
+        }
+        return value
+    }
+    func getValue(_ idx: Int) throws -> Blob {
+        guard let value = elements[idx] as? Blob else {
+            throw QueryError.unexpectedNullValue(name: "column at index \(idx)")
+        }
+        return value
+    }
+}
 
-    fileprivate let handle: OpaquePointer
+public struct Cursor: CursorProtocol {
+    fileprivate let statement: Statement
+    fileprivate var handle: OpaquePointer {
+        statement.handle!
+    }
 
     fileprivate let columnCount: Int
 
     fileprivate init(_ statement: Statement) {
-        handle = statement.handle!
+        self.statement = statement
         columnCount = statement.columnCount
     }
 
-    public subscript(idx: Int) -> Double {
+    public func getValue(_ idx: Int) throws -> Double {
         sqlite3_column_double(handle, Int32(idx))
     }
 
-    public subscript(idx: Int) -> Int64 {
+    public func getValue(_ idx: Int) throws -> Int64 {
         sqlite3_column_int64(handle, Int32(idx))
     }
 
-    public subscript(idx: Int) -> String {
-        String(cString: UnsafePointer(sqlite3_column_text(handle, Int32(idx))))
+    public func getValue(_ idx: Int) throws -> String {
+        guard let text = sqlite3_column_text(handle, Int32(idx)) else {
+            throw QueryError.unexpectedNullValue(name: "column at index \(idx)")
+        }
+        return String(cString: UnsafePointer(text))
     }
 
-    public subscript(idx: Int) -> Blob {
+    public func getValue(_ idx: Int) throws -> Blob {
         if let pointer = sqlite3_column_blob(handle, Int32(idx)) {
             let length = Int(sqlite3_column_bytes(handle, Int32(idx)))
             return Blob(bytes: pointer, length: length)
@@ -292,48 +365,20 @@ public struct Cursor {
         }
     }
 
-    // MARK: -
-
-    public subscript(idx: Int) -> Bool {
-        Bool.fromDatatypeValue(self[idx])
-    }
-
-    public subscript(idx: Int) -> Int {
-        Int.fromDatatypeValue(self[idx])
-    }
-
-}
-
-/// Cursors provide direct access to a statement’s current row.
-extension Cursor: Sequence {
-
-    public subscript(idx: Int) -> Binding? {
+    public func getValue(_ idx: Int) throws -> Binding? {
         switch sqlite3_column_type(handle, Int32(idx)) {
         case SQLITE_BLOB:
-            return self[idx] as Blob
+            return try getValue(idx) as Blob
         case SQLITE_FLOAT:
-            return self[idx] as Double
+            return try getValue(idx) as Double
         case SQLITE_INTEGER:
-            return self[idx] as Int64
+            return try getValue(idx) as Int64
         case SQLITE_NULL:
             return nil
         case SQLITE_TEXT:
-            return self[idx] as String
+            return try getValue(idx) as String
         case let type:
             fatalError("unsupported column type: \(type)")
         }
     }
-
-    public func makeIterator() -> AnyIterator<Binding?> {
-        var idx = 0
-        return AnyIterator {
-            if idx >= columnCount {
-                return .none
-            } else {
-                idx += 1
-                return self[idx - 1]
-            }
-        }
-    }
-
 }

Sources/SQLite/Schema/Connection+Schema.swift

@@ -14,10 +14,10 @@ public extension Connection {
     // https://sqlite.org/pragma.html#pragma_foreign_key_check
     func foreignKeyCheck(table: String? = nil) throws -> [ForeignKeyError] {
         try run("PRAGMA foreign_key_check" + (table.map { "(\($0.quote()))" } ?? ""))
-            .compactMap { (row: [Binding?]) -> ForeignKeyError? in
-                guard let table = row[0] as? String,
-                      let rowId = row[1] as? Int64,
-                      let target = row[2] as? String else { return nil }
+            .compactMap { (row: Cursor) -> ForeignKeyError? in
+                guard let table = row.getValue(0) as String?,
+                      let rowId = row.getValue(1) as Int64?,
+                      let target = row.getValue(2) as String? else { return nil }
 
                 return ForeignKeyError(from: table, rowId: rowId, to: target)
             }
@@ -29,7 +29,7 @@ public extension Connection {
         precondition(table == nil || supports(.partialIntegrityCheck), "partial integrity check not supported")
 
         return try run("PRAGMA integrity_check" + (table.map { "(\($0.quote()))" } ?? ""))
-            .compactMap { $0[0] as? String }
+            .compactMap { $0.getValue(0) as String? }
             .filter { $0 != "ok" }
     }
 }

Sources/SQLite/Typed/Query+Lazy.swift

@@ -0,0 +1,57 @@
+//
+// SQLite.swift
+// https://github.com/stephencelis/SQLite.swift
+// Copyright © 2014-2015 Stephen Celis.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+
+extension Array where Element == LazySequence<AnyIterator<Row>> {
+    @available(swift, deprecated: 1, message: "Please use return value of prepare as Array directly")
+    public init(_ values: Element) {
+        preconditionFailure("Please use return value of prepare as Array directly")
+    }
+}
+
+extension Connection {
+    @_disfavoredOverload
+    public func prepare(_ query: QueryType) throws -> [Row] {
+        let expression = query.expression
+        let statement = try prepare(expression.template, expression.bindings)
+
+        let columnNames = try columnNamesForQuery(query)
+
+        return Array(AnyIterator {
+            statement.next().map { cursor in
+                Row(columnNames, (0..<columnNames.count).map({
+                    try? cursor.getValue($0) as Binding?
+                }))
+            }
+        })
+    }
+
+    public func prepare(_ query: QueryType) throws -> LazySequence<AnyIterator<Row>> {
+        let expression = query.expression
+        let statement = try prepare(expression.template, expression.bindings)
+
+        let columnNames = try columnNamesForQuery(query)
+
+        return AnyIterator { statement.next().map { Row(columnNames, $0) } }.lazy
+    }
+}