Files
swift-mirror/stdlib/private/OSLog/OSLog.swift
Ravi Kandhadai 592bca7202 [oslog] [stdlib-private] Add a prototype of the new os_log swift APIs
that accept string interpolations.

The prototypes are added to stdlib/private directory and will be
used only in tests and in experimental code.
2019-03-14 15:26:21 -07:00

70 lines
2.4 KiB
Swift

//===----------------- OSLog.swift ----------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===-----------------------------------------------------------------------===//
// This file contains the new swift APIs for OS log that accept string
// interpolations. This is a prototype meant for experimentation and testing.
// Do not use it outside of tests.
@_exported import os
@available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
public struct Logger {
internal let logObject: OSLog
/// Create a custom OS log object.
public init(subsystem: String, category: String) {
logObject = OSLog(subsystem: subsystem, category: category)
}
/// Return the default OS log object.
public init() {
logObject = OSLog.default
}
/// Log a string interpolation at a given level. The level is `default` if
/// it is not specified.
public func log(level: OSLogType = .default, _ message: OSLogMessage) {
osLog(logObject, level, message)
}
// TODO: define overloads for logging at specific levels: debug, info, notice,
// error, fault based on the Swift forum "logging-levels" discussion.
}
/// Given an instance of the custom string interpolation type: `OSLogMessage`,
/// extract the format string, serialize the arguments to a byte buffer,
/// and pass them to the OS logging system.
@available(macOS 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
internal func osLog(
_ logObject: OSLog,
_ logLevel: OSLogType,
_ message: OSLogMessage
) {
guard logObject.isEnabled(type: logLevel) else { return }
let bufferSize = message.bufferSize
let bufferMemory = UnsafeMutablePointer<UInt8>.allocate(capacity: bufferSize)
var builder = OSLogByteBufferBuilder(bufferMemory)
message.serializeArguments(into: &builder)
message.formatString.withCString { cFormatString in
___os_log_impl(UnsafeMutableRawPointer(mutating: #dsohandle),
logObject,
logLevel,
cFormatString,
bufferMemory,
UInt32(bufferSize))
}
bufferMemory.deallocate()
}