Update LocalFS to use FileManager for all operations

LocalFS was using some posix APIs (stat, mkdir, chmod, chown, etc)
with some being used in Windows which mean long filenames would fail in
some cases, this cleans that up making all platforms that same

Author: daveinglis

Sources/SWBCore/SpecImplementations/Tools/SwiftCompiler.swift

@@ -526,7 +526,7 @@ public final class SwiftCommandOutputParser: TaskOutputParser {
             serializedDiagnosticsPaths.filter { path in
                 // rdar://91295617 (Swift produces empty serialized diagnostics if there are none which is not parseable by clang_loadDiagnostics)
                 do {
-                    return try fs.exists(path) && fs.getFileInfo(path).statBuf.st_size > 0
+                    return try fs.exists(path) && fs.getFileInfo(path).size > 0
                 } catch {
                     return false
                 }

Sources/SWBLLBuild/LowLevelBuildSystem.swift

@@ -11,11 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 public import SWBUtil
-#if os(Windows)
-private import SWBLibc
-#else
 public import SWBLibc
-#endif
 
 // Re-export all APIs from llbuild bindings.
 @_exported public import llbuild
@@ -25,7 +21,34 @@ public import SWBLibc
 #endif
 
 // Filesystem adaptors for SWBLLBuild.FileSystem.
-extension SWBUtil.FileInfo: SWBLLBuild.FileInfo {}
+extension SWBUtil.FileInfo: SWBLLBuild.FileInfo {
+
+    public init(_ statBuf: stat) {
+        // This should be remove from llbuild FileInfo protocol as it just not needed, would also be nice to remove the stat requirement too.
+        preconditionFailure()
+    }
+    
+    public var statBuf: stat {
+        var statBuf: stat = stat()
+
+        statBuf.st_dev = numericCast(self.deviceID)
+        statBuf.st_ino = numericCast(self.iNode)
+        statBuf.st_mode = numericCast(self.permissions)
+        statBuf.st_size = numericCast(self.size)
+        #if canImport(Darwin)
+        statBuf.st_mtimespec.tv_sec = numericCast(self.modificationTimestamp)
+        statBuf.st_mtimespec.tv_nsec = self.modificationNanoseconds
+        #elseif os(Windows)
+        statBuf.st_mtime = self.modificationTimestamp
+        #elseif canImport(Glibc) || canImport(Musl) || canImport(Android)
+        statBuf.st_mtim.tv_sec = numericCast(self.modificationTimestamp)
+        statBuf.st_mtim.tv_nsec = self.modificationNanoseconds
+        #else
+        #error("Not implemented for this platform")
+        #endif
+        return statBuf
+    }
+}
 
 public final class FileSystemImpl: FileSystem {
 

Sources/SWBTaskExecution/TaskActions/ODRAssetPackManifestTaskAction.swift

@@ -108,7 +108,7 @@ fileprivate extension FSProxy {
 
         try traverse(path) { subPath -> Void in
             let info = try getLinkFileInfo(subPath)
-            uncompressedSize += Int(info.statBuf.st_size)
+            uncompressedSize += Int(info.size)
             newestModTime = max(newestModTime, info.modificationDate)
         }