Switch to FileMetadata to use statx instead of stat on Linux and Apple platforms (#1772)

* Switch to FileMetadata to use st_birthtimespec on Apple platforms

#1755

* Use statx instead of stat on Linux

* Fixup calling statx

* Missing file

* Hardcode __NR_statx for Linux X64

* More platforms

* Fallback if statx isn't available

Also fallback if STATX_BTIME isn't set

Author: swankjesse

gradle.properties

@@ -8,7 +8,9 @@ android.defaults.buildfeatures.renderscript=false
 android.defaults.buildfeatures.resvalues=false
 android.defaults.buildfeatures.shaders=false
 
+kotlin.mpp.applyDefaultHierarchyTemplate=false
 kotlin.mpp.commonizerLogLevel=info
+kotlin.mpp.enableCInteropCommonization=true
 kotlin.mpp.stability.nowarn=true
 
 GROUP=com.squareup.okio

okio-testing-support/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompileTool
+
 plugins {
   kotlin("multiplatform")
   id("app.cash.burst")
@@ -19,6 +21,7 @@ kotlin {
         api(projects.okio)
         api(libs.kotlin.test)
         api(libs.burst.runtime)
+        api(libs.test.assertk)
       }
     }
 
@@ -72,3 +75,34 @@ kotlin {
     }
   }
 }
+
+/*
+ * AbstractFileSystemTest expects a file with specific metadata:
+ *
+ *   path: build/AbstractFileSystemTestFiles/metadata.txt
+ *   createdAt: 2026-01-01T01:01:01Z
+ *   lastModifiedAt: 2026-02-02T02:02:02Z
+ *
+ * It would be nicer to do this in the test itself with exec(), but we don't yet have a handy
+ * multiplatform API for that.
+ */
+val touchAbstractFileSystemTestFilesCreatedAt by tasks.registering(Exec::class) {
+  val sampleFile = project.file("build/AbstractFileSystemTestFiles/metadata.txt")
+  doFirst {
+    sampleFile.parentFile.mkdirs()
+  }
+  environment("TZ" to "UTC")
+  commandLine("touch", "-t", "202601010101.01", sampleFile.path)
+}
+val touchAbstractFileSystemTestFilesModifiedAt by tasks.registering(Exec::class) {
+  dependsOn(touchAbstractFileSystemTestFilesCreatedAt)
+  val sampleFile = project.file("build/AbstractFileSystemTestFiles/metadata.txt")
+  environment("TZ" to "UTC")
+  commandLine("touch", "-t", "202602020202.02", sampleFile.path)
+}
+tasks.withType<KotlinCompileTool> {
+  dependsOn(
+    touchAbstractFileSystemTestFilesCreatedAt,
+    touchAbstractFileSystemTestFilesModifiedAt,
+  )
+}

okio-testing-support/src/commonMain/kotlin/okio/AbstractFileSystemTest.kt

@@ -1471,6 +1471,27 @@ abstract class AbstractFileSystemTest(
     assertInRange(metadata.lastAccessedAt, minTime, maxTime)
   }
 
+  /** https://github.com/square/okio/issues/1755 */
+  @Test
+  fun fileMetadataTimestampsAreDistinct() {
+    if (fileSystem.isFakeFileSystem) return
+    if (fileSystem is ForwardingFileSystem) return
+    if (isJimFileSystem()) return
+    if (!fileSystemHasGoodMetadata) return
+
+    // These timestamps are hardcoded in the following Gradle tasks:
+    //   :okio-testing-support:touchAbstractFileSystemTestFilesCreatedAt
+    //   :okio-testing-support:touchAbstractFileSystemTestFilesModifiedAt
+    val createdAt = fromIso8601String("2026-01-01T01:01:01Z")
+    val lastModifiedAt = fromIso8601String("2026-02-02T02:02:02Z")
+
+    val path = okioRoot / "okio-testing-support" / "build/AbstractFileSystemTestFiles/metadata.txt"
+    val metadata = fileSystem.metadata(path)
+    assertTrue(metadata.isRegularFile)
+    assertInRange(metadata.createdAt, createdAt, createdAt)
+    assertInRange(metadata.lastModifiedAt, lastModifiedAt, lastModifiedAt)
+  }
+
   @Test
   fun directoryMetadata() {
     val minTime = clock.now()

okio-testing-support/src/commonMain/kotlin/okio/TestingCommon.kt

@@ -40,6 +40,14 @@ fun randomToken(length: Int) = Random.nextBytes(length).toByteString(0, length).
 
 expect fun isBrowser(): Boolean
 
+/**
+ * Returns true if the host file system probably exposes metadata like file creation time.
+ *
+ * The file system that GitHub actions gives us doesn't do anything when we `touch` a file.
+ */
+val fileSystemHasGoodMetadata: Boolean
+  get() = getEnv("GITHUB_WORKSPACE") == null
+
 val FileMetadata.createdAt: Instant?
   get() {
     val createdAt = createdAtMillis ?: return null
@@ -58,6 +66,9 @@ val FileMetadata.lastAccessedAt: Instant?
     return Instant.fromEpochMilliseconds(lastAccessedAt)
   }
 
+fun fromIso8601String(iso8601String: String): Instant =
+  Instant.fromEpochMilliseconds(Instant.parse(iso8601String).toEpochMilliseconds())
+
 expect val FileSystem.isFakeFileSystem: Boolean
 
 expect val FileSystem.allowSymlinks: Boolean

okio/build.gradle.kts

@@ -3,9 +3,11 @@ import com.vanniktech.maven.publish.JavadocJar
 import com.vanniktech.maven.publish.KotlinMultiplatform
 import com.vanniktech.maven.publish.MavenPublishBaseExtension
 import kotlinx.validation.ApiValidationExtension
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTargetWithTests
 import org.jetbrains.kotlin.gradle.plugin.mpp.NativeBuildType
 import org.jetbrains.kotlin.gradle.plugin.mpp.TestExecutable
+import org.jetbrains.kotlin.konan.target.Family
 
 plugins {
   kotlin("multiplatform")
@@ -153,9 +155,9 @@ kotlin {
           nativeMain.dependsOn(zlibMain)
           nativeMain.dependsOn(systemFileSystemMain)
           createSourceSet(
-              "mingwMain",
-              parent = nativeMain,
-              children = mingwTargets,
+            "mingwMain",
+            parent = nativeMain,
+            children = mingwTargets,
           ).also { mingwMain ->
             mingwMain.dependsOn(nonAppleMain)
             mingwMain.dependsOn(nonJsMain)
@@ -164,13 +166,23 @@ kotlin {
             .also { unixMain ->
               unixMain.dependsOn(nonJsMain)
               createSourceSet(
-                  "linuxMain",
-                  parent = unixMain,
-                  children = linuxTargets,
+                "linuxMain",
+                parent = unixMain,
+                children = linuxTargets,
               ).also { linuxMain ->
                 linuxMain.dependsOn(nonAppleMain)
               }
-              createSourceSet("appleMain", parent = unixMain, children = appleTargets)
+              createSourceSet(
+                name = "appleMain",
+                parent = unixMain,
+                children = appleTargets,
+              ).also { appleMain ->
+                createSourceSet(
+                  name = "appleNonMacosX64Main",
+                  parent = appleMain,
+                  children = appleTargets - "macosX64",
+                )
+              }
             }
         }
 
@@ -197,6 +209,17 @@ kotlin {
     }
   }
 
+  targets.withType<KotlinNativeTarget> {
+    if (konanTarget.family == Family.LINUX) {
+      compilations["main"].cinterops.create("linux") {
+        packageName("okio.internal.linux")
+        headers(
+          File(project.projectDir, "src/linuxMain/headers/include/uapi/linux/stat.h"),
+          File(project.projectDir, "src/linuxMain/headers/okio_statx.h"),
+        )
+      }
+    }
+  }
   targets.withType<KotlinNativeTargetWithTests<*>> {
     binaries {
       // Configure a separate test where code runs in background

…pleMain/kotlin/okio/ApplePosixVariant.kt …n/kotlin/okio/NonMacosX64PosixVariant.ktokio/src/appleMain/kotlin/okio/ApplePosixVariant.kt renamed to okio/src/appleNonMacosX64Main/kotlin/okio/NonMacosX64PosixVariant.kt okio/src/appleMain/kotlin/okio/ApplePosixVariant.kt renamed to okio/src/appleNonMacosX64Main/kotlin/okio/NonMacosX64PosixVariant.kt

@@ -36,9 +36,9 @@ internal actual fun PosixFileSystem.variantMetadataOrNull(path: Path): FileMetad
     return@memScoped FileMetadata(
       isRegularFile = stat.st_mode.toInt() and S_IFMT == S_IFREG,
       isDirectory = stat.st_mode.toInt() and S_IFMT == S_IFDIR,
-      symlinkTarget = symlinkTarget(stat, path),
+      symlinkTarget = symlinkTarget(stat.st_mode.toInt(), path),
       size = stat.st_size,
-      createdAtMillis = stat.st_ctimespec.epochMillis,
+      createdAtMillis = stat.st_birthtimespec.epochMillis,
       lastModifiedAtMillis = stat.st_mtimespec.epochMillis,
       lastAccessedAtMillis = stat.st_atimespec.epochMillis,
     )

okio/src/linuxMain/headers/README.md

@@ -0,0 +1,8 @@
+# Linux User API
+
+This directory includes files from the Linux kernel user API, used as symbols to build Okio against.
+The license 'GPL-2.0 WITH Linux-syscall-note' permits us to build against these symbols without
+being a derived work.
+
+https://github.com/torvalds/linux/blob/master/LICENSES/preferred/GPL-2.0
+https://github.com/torvalds/linux/blob/master/LICENSES/exceptions/Linux-syscall-note