log freestanding 추가

Author: minsOne

Sources/MacroKit/ExpressionMacros.swift

@@ -1,3 +1,5 @@
+@_exported import os.log
+
 /// A macro that produces both a value and a string containing the
 /// source code that generated the value. For example,
 ///
@@ -6,3 +8,6 @@
 /// produces a tuple `(x + y, "x + y")`.
 @freestanding(expression)
 public macro stringify<T>(_ value: T) -> (T, String) = #externalMacro(module: "Macros", type: "StringifyMacro")
+
+@freestanding(expression)
+public macro log(level: OSLogType, _ message: String) = #externalMacro(module: "Macros", type: "LoggingExpressionMacros")

Sources/MacroKit/MemberMacros.swift

@@ -18,9 +18,9 @@ public macro Logging() = #externalMacro(module: "Macros", type: "LoggingMacro")
 // MARK: - Helper
 
 public enum LoggingMacroHelper {
-    public static func generateLogger(_ fileID: String = #fileID, category: String) -> Logger {
+    public static func generateOSLog(_ fileID: String = #fileID, category: String) -> OSLog {
         let subsystem = fileID.components(separatedBy: "/").first.map { "kr.minsone.\($0)" }
-        return subsystem.map { Logger(subsystem: $0, category: category) }
-            ?? Logger()
+        return subsystem.flatMap { OSLog(subsystem: $0, category: category) }
+            ?? .default
     }
 }

Sources/MacroKitClient/main.swift

@@ -32,7 +32,7 @@ print("cat is \(cat.isCat)")
 @Logging
 class LogModel {
     func log() {
-        logger.debug("Msg")
+        #log(level: .debug, "log messsage")
     }
 }
 

Sources/Macros/Expression/LoggingExpressionMacros.swift

@@ -0,0 +1,59 @@
+import SwiftDiagnostics
+import SwiftSyntax
+import SwiftSyntaxMacros
+
+/// OS 버전에 따라 Logger의 호출이 달라지므로, 조건에 따라 변경이 필요함
+public struct LoggingExpressionMacros: ExpressionMacro {
+    public static func expansion(
+        of node: some FreestandingMacroExpansionSyntax,
+        in context: some MacroExpansionContext
+    ) -> ExprSyntax {
+        let argumentList = node.argumentList
+        guard
+            argumentList.count == 2,
+            let firstElement = argumentList.first,
+            let secondElement = argumentList.last
+        else {
+            fatalError("compiler bug: the macro does not have any arguments")
+        }
+
+        let oslogType = firstElement.expression
+            .as(MemberAccessExprSyntax.self)?
+            .declName.baseName.text
+        let msg = secondElement.expression
+            .as(StringLiteralExprSyntax.self)?
+            .segments.first?
+            .as(StringSegmentSyntax.self)?
+            .content.text
+
+        guard
+            let oslogType, let msg
+        else {
+            fatalError("compiler bug: the macro does not have any arguments")
+        }
+
+        return "\(raw: generateExpr(oslogType: oslogType, msg: msg))"
+    }
+
+    private static func generateExpr(oslogType: String, msg: String) -> String {
+        """
+        {
+          #if os(iOS)
+            if #available(iOS 14.0, *) {
+              Logger(logger).log(level: .\(oslogType), "\(msg)")
+            } else {
+              \(debug(oslogType: oslogType, msg: msg))
+            }
+          #else
+            \(debug(oslogType: oslogType, msg: msg))
+          #endif
+        }()
+        """
+    }
+
+    private static func debug(oslogType: String, msg: String) -> String {
+        """
+        os_log(.\(oslogType), log: logger, "\(msg)")
+        """
+    }
+}

Sources/Macros/MacrosPlugin.swift

@@ -8,6 +8,7 @@ struct MacrosPlugin: CompilerPlugin {
     static var expressionMacros: [Macro.Type] {
         [
             StringifyMacro.self,
+            LoggingExpressionMacros.self,
         ]
     }
 

Sources/Macros/Member/Logging/LoggingMacro.swift

@@ -34,8 +34,8 @@ public struct LoggingMacro: MemberMacro {
         return [
             DeclSyntax(
                 """
-                lazy var logger: Logger = {
-                    LoggingMacroHelper.generateLogger(category: String(describing: Self.self))
+                lazy var logger: OSLog = {
+                    LoggingMacroHelper.generateOSLog(category: String(describing: Self.self))
                 }()
                 """),
         ]

Tests/MacroKitTests/Expression/LoggingExpressionMacros.swift

@@ -0,0 +1,28 @@
+import Macros
+import SwiftSyntaxMacros
+import SwiftSyntaxMacrosTestSupport
+import XCTest
+
+final class LoggingExpressionMacrosTests: XCTestCase {
+    func testMacro() throws {
+        assertMacroExpansion(
+            #"""
+            #log(level: .debug, "message")
+            """#,
+            expandedSource: #"""
+            {
+              #if os(iOS)
+                if #available (iOS 14.0, *) {
+                  Logger(logger).log(level: .debug, "message")
+                } else {
+                  os_log(.debug, log: logger, "message")
+                }
+              #else
+                os_log(.debug, log: logger, "message")
+              #endif
+            }()
+            """#,
+            macros: ["log": LoggingExpressionMacros.self]
+        )
+    }
+}