[PlaygroundLogger] Use a wrapper static inline C function to get and set PGLThreadIsLogging.

This is to insulate from any issues which might arise because Swift may or may not handle `__thread` variables correctly.

Author: cwakamo

PlaygroundLogger/PlaygroundLogger/LegacySupport/LegacyEntrypoints.swift

@@ -36,9 +36,9 @@ fileprivate func legacySendDataStub(_: NSData) -> Void {
 
 @_silgen_name("playground_log_hidden")
 public func legacyLog<T>(instance: T, name: String, id: Int, startLine: Int, endLine: Int, startColumn: Int, endColumn: Int) -> AnyObject? {
-    guard !PGLThreadIsLogging else { return nil }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return nil }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(describingResult: instance, named: name, withPolicy: .default, startLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -73,9 +73,9 @@ public func legacyLog<T>(instance: T, name: String, id: Int, startLine: Int, end
 
 @_silgen_name ("playground_log_scope_entry")
 public func legacyLogScopeEntry(startLine: Int, endLine: Int, startColumn: Int, endColumn: Int) -> AnyObject? {
-    guard !PGLThreadIsLogging else { return nil }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return nil }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(scopeEntryWithStartLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -87,9 +87,9 @@ public func legacyLogScopeEntry(startLine: Int, endLine: Int, startColumn: Int,
 
 @_silgen_name ("playground_log_scope_exit")
 public func legacyLogScopeExit(startLine: Int, endLine: Int, startColumn: Int, endColumn: Int) -> AnyObject? {
-    guard !PGLThreadIsLogging else { return nil }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return nil }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(scopeExitWithStartLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -101,9 +101,9 @@ public func legacyLogScopeExit(startLine: Int, endLine: Int, startColumn: Int, e
 
 @_silgen_name ("playground_log_postprint")
 public func legacyLogPostPrint(startLine: Int, endLine: Int, startColumn: Int, endColumn: Int) -> AnyObject? {
-    guard !PGLThreadIsLogging else { return nil }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return nil }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let printedString = Thread.current.threadDictionary[printedStringThreadDictionaryKey] as! String? ?? ""
 

PlaygroundLogger/PlaygroundLogger/LoggerEntrypoints.swift

@@ -19,9 +19,9 @@ func logResult(_ result: Any,
                endLine: Int,
                startColumn: Int,
                endColumn: Int) {
-    guard !PGLThreadIsLogging else { return }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(describingResult: result, named: name, withPolicy: .default, startLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -58,9 +58,9 @@ func logScopeEntry(startLine: Int,
                    endLine: Int,
                    startColumn: Int,
                    endColumn: Int) {
-    guard !PGLThreadIsLogging else { return }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(scopeEntryWithStartLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -74,9 +74,9 @@ func logScopeExit(startLine: Int,
                   endLine: Int,
                   startColumn: Int,
                   endColumn: Int) {
-    guard !PGLThreadIsLogging else { return }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     let packet = LogPacket(scopeExitWithStartLine: startLine, endLine: endLine, startColumn: startColumn, endColumn: endColumn)
 
@@ -90,7 +90,7 @@ let printedStringThreadDictionaryKey: NSString = "org.swift.PlaygroundLogger.pri
 
 func printHook(string: String) {
     // Don't store the printed string if we're already logging elsewhere in this thread.
-    guard !PGLThreadIsLogging else { return }
+    guard !PGLGetThreadIsLogging() else { return }
 
     Thread.current.threadDictionary[printedStringThreadDictionaryKey] = string as NSString
 }
@@ -99,9 +99,9 @@ func logPostPrint(startLine: Int,
                   endLine: Int,
                   startColumn: Int,
                   endColumn: Int) {
-    guard !PGLThreadIsLogging else { return }
-    PGLThreadIsLogging = true
-    defer { PGLThreadIsLogging = false }
+    guard !PGLGetThreadIsLogging() else { return }
+    PGLSetThreadIsLogging(true)
+    defer { PGLSetThreadIsLogging(false) }
 
     guard let printedString = Thread.current.threadDictionary[printedStringThreadDictionaryKey] as! String? else {
         return

PlaygroundLogger/PlaygroundLogger/Utilities/PGLThreadIsLogging.h

@@ -24,4 +24,14 @@ __BEGIN_DECLS
 /// themselves logged.
 extern __thread bool PGLThreadIsLogging;
 
+/// A helper function to get the value of `PGLThreadIsLogging` safely from Swift.
+static inline bool PGLGetThreadIsLogging(void) {
+    return PGLThreadIsLogging;
+}
+
+/// A helper function to set the value of `PGLThreadIsLogging` safely from Swift.
+static inline void PGLSetThreadIsLogging(bool threadIsLogging) {
+    PGLThreadIsLogging = threadIsLogging;
+}
+
 __END_DECLS