mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
4ab45dfe20
This is a giant squashing of a lot of individual changes prototyping a switch of String in Swift 5 to be natively encoded as UTF-8. It includes what's necessary for a functional prototype, dropping some history, but still leaves plenty of history available for future commits. My apologies to anyone trying to do code archeology between this commit and the one prior. This was the lesser of evils.
599 lines
20 KiB
Swift
599 lines
20 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftShims
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//===----------------------------------------------------------------------===//
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// Input/Output interfaces
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//===----------------------------------------------------------------------===//
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/// A type that can be the target of text-streaming operations.
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///
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/// You can send the output of the standard library's `print(_:to:)` and
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/// `dump(_:to:)` functions to an instance of a type that conforms to the
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/// `TextOutputStream` protocol instead of to standard output. Swift's
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/// `String` type conforms to `TextOutputStream` already, so you can capture
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/// the output from `print(_:to:)` and `dump(_:to:)` in a string instead of
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/// logging it to standard output.
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///
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/// var s = ""
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/// for n in 1...5 {
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/// print(n, terminator: "", to: &s)
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/// }
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/// // s == "12345"
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///
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/// Conforming to the TextOutputStream Protocol
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/// ===========================================
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///
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/// To make your custom type conform to the `TextOutputStream` protocol,
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/// implement the required `write(_:)` method. Functions that use a
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/// `TextOutputStream` target may call `write(_:)` multiple times per writing
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/// operation.
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///
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/// As an example, here's an implementation of an output stream that converts
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/// any input to its plain ASCII representation before sending it to standard
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/// output.
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///
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/// struct ASCIILogger: TextOutputStream {
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/// mutating func write(_ string: String) {
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/// let ascii = string.unicodeScalars.lazy.map { scalar in
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/// scalar == "\n"
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/// ? "\n"
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/// : scalar.escaped(asASCII: true)
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/// }
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/// print(ascii.joined(separator: ""), terminator: "")
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/// }
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/// }
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///
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/// The `ASCIILogger` type's `write(_:)` method processes its string input by
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/// escaping each Unicode scalar, with the exception of `"\n"` line returns.
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/// By sending the output of the `print(_:to:)` function to an instance of
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/// `ASCIILogger`, you invoke its `write(_:)` method.
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///
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/// let s = "Hearts ♡ and Diamonds ♢"
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/// print(s)
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/// // Prints "Hearts ♡ and Diamonds ♢"
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///
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/// var asciiLogger = ASCIILogger()
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/// print(s, to: &asciiLogger)
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/// // Prints "Hearts \u{2661} and Diamonds \u{2662}"
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public protocol TextOutputStream {
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mutating func _lock()
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mutating func _unlock()
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/// Appends the given string to the stream.
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mutating func write(_ string: String)
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mutating func _writeASCII(_ buffer: UnsafeBufferPointer<UInt8>)
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}
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extension TextOutputStream {
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public mutating func _lock() {}
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public mutating func _unlock() {}
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public mutating func _writeASCII(_ buffer: UnsafeBufferPointer<UInt8>) {
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write(String._fromASCII(buffer))
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}
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}
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/// A source of text-streaming operations.
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///
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/// Instances of types that conform to the `TextOutputStreamable` protocol can
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/// write their value to instances of any type that conforms to the
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/// `TextOutputStream` protocol. The Swift standard library's text-related
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/// types, `String`, `Character`, and `Unicode.Scalar`, all conform to
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/// `TextOutputStreamable`.
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///
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/// Conforming to the TextOutputStreamable Protocol
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/// =====================================
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///
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/// To add `TextOutputStreamable` conformance to a custom type, implement the
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/// required `write(to:)` method. Call the given output stream's `write(_:)`
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/// method in your implementation.
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public protocol TextOutputStreamable {
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/// Writes a textual representation of this instance into the given output
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/// stream.
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func write<Target : TextOutputStream>(to target: inout Target)
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}
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/// A type with a customized textual representation.
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///
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/// Types that conform to the `CustomStringConvertible` protocol can provide
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/// their own representation to be used when converting an instance to a
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/// string. The `String(describing:)` initializer is the preferred way to
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/// convert an instance of *any* type to a string. If the passed instance
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/// conforms to `CustomStringConvertible`, the `String(describing:)`
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/// initializer and the `print(_:)` function use the instance's custom
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/// `description` property.
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///
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/// Accessing a type's `description` property directly or using
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/// `CustomStringConvertible` as a generic constraint is discouraged.
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///
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/// Conforming to the CustomStringConvertible Protocol
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/// ==================================================
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///
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/// Add `CustomStringConvertible` conformance to your custom types by defining
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/// a `description` property.
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///
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/// For example, this custom `Point` struct uses the default representation
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/// supplied by the standard library:
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///
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/// struct Point {
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/// let x: Int, y: Int
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/// }
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///
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/// let p = Point(x: 21, y: 30)
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/// print(p)
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/// // Prints "Point(x: 21, y: 30)"
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///
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/// After implementing the `description` property and declaring
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/// `CustomStringConvertible` conformance, the `Point` type provides its own
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/// custom representation.
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///
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/// extension Point: CustomStringConvertible {
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/// var description: String {
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/// return "(\(x), \(y))"
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/// }
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/// }
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///
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/// print(p)
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/// // Prints "(21, 30)"
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public protocol CustomStringConvertible {
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/// A textual representation of this instance.
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///
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/// Calling this property directly is discouraged. Instead, convert an
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/// instance of any type to a string by using the `String(describing:)`
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/// initializer. This initializer works with any type, and uses the custom
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/// `description` property for types that conform to
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/// `CustomStringConvertible`:
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///
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/// struct Point: CustomStringConvertible {
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/// let x: Int, y: Int
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///
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/// var description: String {
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/// return "(\(x), \(y))"
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/// }
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/// }
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///
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/// let p = Point(x: 21, y: 30)
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/// let s = String(describing: p)
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/// print(s)
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/// // Prints "(21, 30)"
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///
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/// The conversion of `p` to a string in the assignment to `s` uses the
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/// `Point` type's `description` property.
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var description: String { get }
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}
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/// A type that can be represented as a string in a lossless, unambiguous way.
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///
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/// For example, the integer value 1050 can be represented in its entirety as
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/// the string "1050".
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///
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/// The description property of a conforming type must be a value-preserving
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/// representation of the original value. As such, it should be possible to
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/// re-create an instance from its string representation.
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public protocol LosslessStringConvertible : CustomStringConvertible {
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/// Instantiates an instance of the conforming type from a string
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/// representation.
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init?(_ description: String)
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}
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/// A type with a customized textual representation suitable for debugging
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/// purposes.
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///
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/// Swift provides a default debugging textual representation for any type.
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/// That default representation is used by the `String(reflecting:)`
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/// initializer and the `debugPrint(_:)` function for types that don't provide
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/// their own. To customize that representation, make your type conform to the
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/// `CustomDebugStringConvertible` protocol.
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///
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/// Because the `String(reflecting:)` initializer works for instances of *any*
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/// type, returning an instance's `debugDescription` if the value passed
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/// conforms to `CustomDebugStringConvertible`, accessing a type's
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/// `debugDescription` property directly or using
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/// `CustomDebugStringConvertible` as a generic constraint is discouraged.
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///
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/// - Note: Calling the `dump(_:_:_:_:)` function and printing in the debugger
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/// uses both `String(reflecting:)` and `Mirror(reflecting:)` to collect
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/// information about an instance. If you implement
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/// `CustomDebugStringConvertible` conformance for your custom type, you may
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/// want to consider providing a custom mirror by implementing
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/// `CustomReflectable` conformance, as well.
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///
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/// Conforming to the CustomDebugStringConvertible Protocol
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/// =======================================================
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///
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/// Add `CustomDebugStringConvertible` conformance to your custom types by
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/// defining a `debugDescription` property.
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///
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/// For example, this custom `Point` struct uses the default representation
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/// supplied by the standard library:
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///
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/// struct Point {
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/// let x: Int, y: Int
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/// }
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///
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/// let p = Point(x: 21, y: 30)
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/// print(String(reflecting: p))
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/// // Prints "p: Point = {
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/// // x = 21
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/// // y = 30
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/// // }"
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///
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/// After adding `CustomDebugStringConvertible` conformance by implementing the
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/// `debugDescription` property, `Point` provides its own custom debugging
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/// representation.
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///
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/// extension Point: CustomDebugStringConvertible {
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/// var debugDescription: String {
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/// return "Point(x: \(x), y: \(y))"
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/// }
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/// }
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///
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/// print(String(reflecting: p))
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/// // Prints "Point(x: 21, y: 30)"
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public protocol CustomDebugStringConvertible {
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/// A textual representation of this instance, suitable for debugging.
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///
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/// Calling this property directly is discouraged. Instead, convert an
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/// instance of any type to a string by using the `String(reflecting:)`
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/// initializer. This initializer works with any type, and uses the custom
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/// `debugDescription` property for types that conform to
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/// `CustomDebugStringConvertible`:
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///
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/// struct Point: CustomDebugStringConvertible {
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/// let x: Int, y: Int
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///
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/// var debugDescription: String {
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/// return "(\(x), \(y))"
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/// }
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/// }
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///
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/// let p = Point(x: 21, y: 30)
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/// let s = String(reflecting: p)
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/// print(s)
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/// // Prints "(21, 30)"
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///
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/// The conversion of `p` to a string in the assignment to `s` uses the
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/// `Point` type's `debugDescription` property.
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var debugDescription: String { get }
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}
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//===----------------------------------------------------------------------===//
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// Default (ad-hoc) printing
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//===----------------------------------------------------------------------===//
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@_silgen_name("swift_EnumCaseName")
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internal func _getEnumCaseName<T>(_ value: T) -> UnsafePointer<CChar>?
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@_silgen_name("swift_OpaqueSummary")
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internal func _opaqueSummary(_ metadata: Any.Type) -> UnsafePointer<CChar>?
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/// Do our best to print a value that cannot be printed directly.
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@_semantics("optimize.sil.specialize.generic.never")
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internal func _adHocPrint_unlocked<T, TargetStream : TextOutputStream>(
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_ value: T, _ mirror: Mirror, _ target: inout TargetStream,
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isDebugPrint: Bool
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) {
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func printTypeName(_ type: Any.Type) {
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// Print type names without qualification, unless we're debugPrint'ing.
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target.write(_typeName(type, qualified: isDebugPrint))
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}
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if let displayStyle = mirror.displayStyle {
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switch displayStyle {
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case .optional:
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if let child = mirror.children.first {
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_debugPrint_unlocked(child.1, &target)
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} else {
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_debugPrint_unlocked("nil", &target)
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}
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case .tuple:
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target.write("(")
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var first = true
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for (label, value) in mirror.children {
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if first {
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first = false
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} else {
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target.write(", ")
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}
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if let label = label {
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if !label.isEmpty && label[label.startIndex] != "." {
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target.write(label)
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target.write(": ")
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}
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}
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_debugPrint_unlocked(value, &target)
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}
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target.write(")")
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case .struct:
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printTypeName(mirror.subjectType)
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target.write("(")
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var first = true
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for (label, value) in mirror.children {
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if let label = label {
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if first {
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first = false
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} else {
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target.write(", ")
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}
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target.write(label)
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target.write(": ")
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_debugPrint_unlocked(value, &target)
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}
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}
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target.write(")")
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case .enum:
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if let cString = _getEnumCaseName(value),
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let caseName = String(validatingUTF8: cString) {
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// Write the qualified type name in debugPrint.
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if isDebugPrint {
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printTypeName(mirror.subjectType)
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target.write(".")
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}
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target.write(caseName)
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} else {
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// If the case name is garbage, just print the type name.
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printTypeName(mirror.subjectType)
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}
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if let (_, value) = mirror.children.first {
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if Mirror(reflecting: value).displayStyle == .tuple {
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_debugPrint_unlocked(value, &target)
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} else {
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target.write("(")
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_debugPrint_unlocked(value, &target)
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target.write(")")
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}
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}
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default:
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target.write(_typeName(mirror.subjectType))
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}
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} else if let metatypeValue = value as? Any.Type {
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// Metatype
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printTypeName(metatypeValue)
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} else {
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// Fall back to the type or an opaque summary of the kind
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if let cString = _opaqueSummary(mirror.subjectType),
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let opaqueSummary = String(validatingUTF8: cString) {
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target.write(opaqueSummary)
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} else {
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target.write(_typeName(mirror.subjectType, qualified: true))
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}
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}
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}
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@usableFromInline
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@_semantics("optimize.sil.specialize.generic.never")
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internal func _print_unlocked<T, TargetStream : TextOutputStream>(
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_ value: T, _ target: inout TargetStream
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) {
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// Optional has no representation suitable for display; therefore,
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// values of optional type should be printed as a debug
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// string. Check for Optional first, before checking protocol
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// conformance below, because an Optional value is convertible to a
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// protocol if its wrapped type conforms to that protocol.
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if _isOptional(type(of: value)) {
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let debugPrintable = value as! CustomDebugStringConvertible
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debugPrintable.debugDescription.write(to: &target)
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return
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}
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if case let streamableObject as TextOutputStreamable = value {
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streamableObject.write(to: &target)
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return
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}
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if case let printableObject as CustomStringConvertible = value {
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printableObject.description.write(to: &target)
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return
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}
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if case let debugPrintableObject as CustomDebugStringConvertible = value {
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debugPrintableObject.debugDescription.write(to: &target)
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return
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}
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let mirror = Mirror(reflecting: value)
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_adHocPrint_unlocked(value, mirror, &target, isDebugPrint: false)
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}
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//===----------------------------------------------------------------------===//
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// `debugPrint`
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//===----------------------------------------------------------------------===//
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@_semantics("optimize.sil.specialize.generic.never")
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@inline(never)
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public func _debugPrint_unlocked<T, TargetStream : TextOutputStream>(
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_ value: T, _ target: inout TargetStream
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) {
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if let debugPrintableObject = value as? CustomDebugStringConvertible {
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debugPrintableObject.debugDescription.write(to: &target)
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return
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}
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if let printableObject = value as? CustomStringConvertible {
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printableObject.description.write(to: &target)
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return
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}
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if let streamableObject = value as? TextOutputStreamable {
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streamableObject.write(to: &target)
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return
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}
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let mirror = Mirror(reflecting: value)
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_adHocPrint_unlocked(value, mirror, &target, isDebugPrint: true)
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}
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@_semantics("optimize.sil.specialize.generic.never")
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internal func _dumpPrint_unlocked<T, TargetStream : TextOutputStream>(
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_ value: T, _ mirror: Mirror, _ target: inout TargetStream
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) {
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if let displayStyle = mirror.displayStyle {
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// Containers and tuples are always displayed in terms of their element
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// count
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switch displayStyle {
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case .tuple:
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let count = mirror.children.count
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target.write(count == 1 ? "(1 element)" : "(\(count) elements)")
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return
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case .collection:
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let count = mirror.children.count
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target.write(count == 1 ? "1 element" : "\(count) elements")
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return
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case .dictionary:
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let count = mirror.children.count
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target.write(count == 1 ? "1 key/value pair" : "\(count) key/value pairs")
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return
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case .`set`:
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let count = mirror.children.count
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target.write(count == 1 ? "1 member" : "\(count) members")
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return
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default:
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break
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}
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}
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if let debugPrintableObject = value as? CustomDebugStringConvertible {
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debugPrintableObject.debugDescription.write(to: &target)
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return
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}
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if let printableObject = value as? CustomStringConvertible {
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printableObject.description.write(to: &target)
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return
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}
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if let streamableObject = value as? TextOutputStreamable {
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streamableObject.write(to: &target)
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return
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}
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if let displayStyle = mirror.displayStyle {
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switch displayStyle {
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case .`class`, .`struct`:
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// Classes and structs without custom representations are displayed as
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// their fully qualified type name
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target.write(_typeName(mirror.subjectType, qualified: true))
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return
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case .`enum`:
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target.write(_typeName(mirror.subjectType, qualified: true))
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if let cString = _getEnumCaseName(value),
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let caseName = String(validatingUTF8: cString) {
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target.write(".")
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target.write(caseName)
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}
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return
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default:
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break
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}
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}
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_adHocPrint_unlocked(value, mirror, &target, isDebugPrint: true)
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}
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//===----------------------------------------------------------------------===//
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// OutputStreams
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//===----------------------------------------------------------------------===//
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internal struct _Stdout : TextOutputStream {
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internal init() {}
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internal mutating func _lock() {
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_swift_stdlib_flockfile_stdout()
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}
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internal mutating func _unlock() {
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_swift_stdlib_funlockfile_stdout()
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}
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|
|
|
internal mutating func write(_ string: String) {
|
|
if string.isEmpty { return }
|
|
|
|
_ = string._withUTF8 { utf8 in
|
|
_swift_stdlib_fwrite_stdout(utf8.baseAddress!, 1, utf8.count)
|
|
}
|
|
}
|
|
}
|
|
|
|
extension String : TextOutputStream {
|
|
/// Appends the given string to this string.
|
|
///
|
|
/// - Parameter other: A string to append.
|
|
public mutating func write(_ other: String) {
|
|
self += other
|
|
}
|
|
|
|
public mutating func _writeASCII(_ buffer: UnsafeBufferPointer<UInt8>) {
|
|
self._guts.append(_StringGuts(buffer, isKnownASCII: true))
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Streamables
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
extension String : TextOutputStreamable {
|
|
/// Writes the string into the given output stream.
|
|
///
|
|
/// - Parameter target: An output stream.
|
|
public func write<Target : TextOutputStream>(to target: inout Target) {
|
|
target.write(self)
|
|
}
|
|
}
|
|
|
|
extension Character : TextOutputStreamable {
|
|
/// Writes the character into the given output stream.
|
|
///
|
|
/// - Parameter target: An output stream.
|
|
public func write<Target : TextOutputStream>(to target: inout Target) {
|
|
target.write(String(self))
|
|
}
|
|
}
|
|
|
|
extension Unicode.Scalar : TextOutputStreamable {
|
|
/// Writes the textual representation of the Unicode scalar into the given
|
|
/// output stream.
|
|
///
|
|
/// - Parameter target: An output stream.
|
|
public func write<Target : TextOutputStream>(to target: inout Target) {
|
|
target.write(String(Character(self)))
|
|
}
|
|
}
|
|
|
|
/// A hook for playgrounds to print through.
|
|
public var _playgroundPrintHook : ((String) -> Void)? = nil
|
|
|
|
internal struct _TeeStream<
|
|
L : TextOutputStream,
|
|
R : TextOutputStream
|
|
> : TextOutputStream {
|
|
|
|
internal init(left: L, right: R) {
|
|
self.left = left
|
|
self.right = right
|
|
}
|
|
|
|
internal var left: L
|
|
internal var right: R
|
|
|
|
/// Append the given `string` to this stream.
|
|
internal mutating func write(_ string: String) {
|
|
left.write(string); right.write(string)
|
|
}
|
|
|
|
internal mutating func _lock() { left._lock(); right._lock() }
|
|
internal mutating func _unlock() { right._unlock(); left._unlock() }
|
|
}
|