add swiftUI code

iOS-SwiftUI-Code/GRDB.swift-6.29.3/GRDB/Core/SQLRequest.swift

@@ -0,0 +1,236 @@
+/// An SQL request that can decode database rows.
+///
+/// `SQLRequest` allows you to safely embed raw values in your SQL,
+/// without any risk of syntax errors or SQL injection:
+///
+/// ```swift
+/// extension Player: FetchableRecord {
+///     static func filter(name: String) -> SQLRequest<Player> {
+///         "SELECT * FROM player WHERE name = \(name)"
+///     }
+///
+///     static func maximumScore() -> SQLRequest<Int> {
+///         "SELECT MAX(score) FROM player"
+///     }
+/// }
+///
+/// try dbQueue.read { db in
+///     let players = try Player.filter(name: "O'Brien").fetchAll(db) // [Player]
+///     let maxScore = try Player.maximumScore().fetchOne(db)         // Int?
+/// }
+/// ```
+///
+/// An `SQLRequest` can be created from a string literal or interpolation, as in
+/// the above examples, and from the initializers documented below.
+///
+/// ## Topics
+///
+/// ### Creating an SQL Request from a Literal Value
+///
+/// - ``init(stringLiteral:)``
+/// - ``init(unicodeScalarLiteral:)-84mq8``
+/// - ``init(extendedGraphemeClusterLiteral:)-1sf75``
+///
+/// ### Creating an SQL Request from an Interpolation
+///
+/// - ``init(stringInterpolation:)``
+///
+/// ### Creating an SQL Request from an SQL Literal
+///
+/// - ``init(literal:adapter:cached:)-4vuxn``
+/// - ``init(literal:adapter:cached:)-82f97``
+///
+/// ### Creating an SQL Request from an SQL String
+///
+/// - ``init(sql:arguments:adapter:cached:)-3qq8t``
+/// - ``init(sql:arguments:adapter:cached:)-5ecx2``
+public struct SQLRequest<RowDecoder> {
+    /// There are two statement caches: one "public" for statements generated by
+    /// the user, and one "internal" for the statements generated by GRDB. Those
+    /// are separated so that GRDB has no opportunity to inadvertently modify
+    /// the arguments of user's cached statements.
+    enum Cache {
+        /// The public cache, for library user
+        case `public`
+        
+        /// The internal cache, for GRDB
+        case `internal`
+    }
+    
+    /// The row adapter.
+    public var adapter: (any RowAdapter)?
+    
+    private(set) var sqlLiteral: SQL
+    let cache: Cache?
+    
+    private init(
+        literal sqlLiteral: SQL,
+        adapter: (any RowAdapter)?,
+        fromCache cache: Cache?,
+        type: RowDecoder.Type)
+    {
+        self.sqlLiteral = sqlLiteral
+        self.adapter = adapter
+        self.cache = cache
+    }
+}
+
+extension SQLRequest {
+    /// Creates a request from an SQL string.
+    ///
+    /// ```swift
+    /// let request = SQLRequest<String>(sql: """
+    ///     SELECT name FROM player
+    ///     """)
+    /// let request = SQLRequest<Player>(sql: """
+    ///     SELECT * FROM player WHERE name = ?
+    ///     """, arguments: ["O'Brien"])
+    /// ```
+    ///
+    /// - parameters:
+    ///     - sql: An SQL string.
+    ///     - arguments: Statement arguments.
+    ///     - adapter: Optional RowAdapter.
+    ///     - cached: Defaults to false. If true, the request reuses a cached
+    ///       prepared statement.
+    public init(
+        sql: String,
+        arguments: StatementArguments = StatementArguments(),
+        adapter: (any RowAdapter)? = nil,
+        cached: Bool = false)
+    {
+        self.init(
+            literal: SQL(sql: sql, arguments: arguments),
+            adapter: adapter,
+            fromCache: cached ? .public : nil,
+            type: RowDecoder.self)
+    }
+    
+    /// Creates a request from an ``SQL`` literal.
+    ///
+    /// ``SQL`` literals allow you to safely embed raw values in your SQL,
+    /// without any risk of syntax errors or SQL injection:
+    ///
+    /// ```swift
+    /// let name = "O'Brien"
+    /// let request = SQLRequest<Player>(literal: """
+    ///     SELECT * FROM player WHERE name = \(name)
+    ///     """)
+    /// ```
+    ///
+    /// - parameters:
+    ///     - sqlLiteral: An `SQL` literal.
+    ///     - adapter: Optional RowAdapter.
+    ///     - cached: Defaults to false. If true, the request reuses a cached
+    ///       prepared statement.
+    public init(literal sqlLiteral: SQL, adapter: (any RowAdapter)? = nil, cached: Bool = false) {
+        self.init(
+            literal: sqlLiteral,
+            adapter: adapter,
+            fromCache: cached ? .public : nil,
+            type: RowDecoder.self)
+    }
+}
+
+extension SQLRequest<Row> {
+    /// Creates a request of database rows, from an SQL string.
+    ///
+    /// ```swift
+    /// let request = SQLRequest(sql: """
+    ///     SELECT * FROM player WHERE name = ?
+    ///     """, arguments: ["O'Brien"])
+    /// ```
+    ///
+    /// - parameters:
+    ///     - sql: An SQL string.
+    ///     - arguments: Statement arguments.
+    ///     - adapter: Optional RowAdapter.
+    ///     - cached: Defaults to false. If true, the request reuses a cached
+    ///       prepared statement.
+    public init(
+        sql: String,
+        arguments: StatementArguments = StatementArguments(),
+        adapter: (any RowAdapter)? = nil,
+        cached: Bool = false)
+    {
+        self.init(
+            literal: SQL(sql: sql, arguments: arguments),
+            adapter: adapter,
+            fromCache: cached ? .public : nil,
+            type: Row.self)
+    }
+    
+    /// Creates a request of database rows, from an ``SQL`` literal.
+    ///
+    /// ``SQL`` literals allow you to safely embed raw values in your SQL,
+    /// without any risk of syntax errors or SQL injection:
+    ///
+    /// ```swift
+    /// let name = "O'Brien"
+    /// let request = SQLRequest(literal: """
+    ///     SELECT * FROM player WHERE name = \(name)
+    ///     """)
+    /// ```
+    ///
+    /// - parameters:
+    ///     - sqlLiteral: An `SQL` literal.
+    ///     - adapter: Optional RowAdapter.
+    ///     - cached: Defaults to false. If true, the request reuses a cached
+    ///       prepared statement.
+    public init(literal sqlLiteral: SQL, adapter: (any RowAdapter)? = nil, cached: Bool = false) {
+        self.init(
+            literal: sqlLiteral,
+            adapter: adapter,
+            fromCache: cached ? .public : nil,
+            type: Row.self)
+    }
+}
+
+extension SQLRequest: FetchRequest {
+    public var sqlSubquery: SQLSubquery {
+        .literal(sqlLiteral)
+    }
+    
+    public func fetchCount(_ db: Database) throws -> Int {
+        try SQLRequest<Int>("SELECT COUNT(*) FROM (\(self))").fetchOne(db)!
+    }
+    
+    public func makePreparedRequest(
+        _ db: Database,
+        forSingleResult singleResult: Bool = false)
+    throws -> PreparedRequest
+    {
+        let context = SQLGenerationContext(db)
+        let sql = try sqlLiteral.sql(context)
+        let statement: Statement
+        switch cache {
+        case .none:
+            statement = try db.makeStatement(sql: sql)
+        case .public:
+            statement = try db.cachedStatement(sql: sql)
+        case .internal:
+            statement = try db.internalCachedStatement(sql: sql)
+        }
+        try statement.setArguments(context.arguments)
+        return PreparedRequest(statement: statement, adapter: adapter)
+    }
+}
+
+extension SQLRequest: ExpressibleByStringInterpolation {
+    public init(unicodeScalarLiteral: String) {
+        self.init(sql: unicodeScalarLiteral)
+    }
+    
+    public init(extendedGraphemeClusterLiteral: String) {
+        self.init(sql: extendedGraphemeClusterLiteral)
+    }
+    
+    /// Creates an `SQLRequest` from the given literal SQL string.
+    public init(stringLiteral: String) {
+        self.init(sql: stringLiteral)
+    }
+    
+    public init(stringInterpolation sqlInterpolation: SQLInterpolation) {
+        self.init(literal: SQL(stringInterpolation: sqlInterpolation))
+    }
+}