Implement hostOs detection for web target (#738)

* Implement hostOs detection for web target

* Refactor hostOs initialization in OsArch.js.kt

Instead of using a lazy initialization, this change allows immediate initialization.

* Deprecate incorrect enum OS.JS value in OsArch.kt

Deprecation annotation has been added to JS enum in OsArch. This is done as 'JS' is not a valid host OS name. Added 'Unknown' enum for undefined or unknown cases to handle from now on. Consider using enum 'KotlinBackend' to detect JS.

* Deprecate invalid Arch values and modify hostArch

The Arch values 'JS' and 'WASM' were deprecated as they were found to be invalid. An 'Unknown' value was introduced to accommodate for unforeseen cases in the future. The 'hostArch' value under 'OsArch.js.kt' has been updated accordingly to use this new 'Unknown' value.

* Add OS.Unknown to `when` expressions to make them exhaustive

skiko/src/awtMain/kotlin/org/jetbrains/skiko/Actuals.awt.kt

@@ -36,7 +36,7 @@ internal actual fun makeDefaultRenderFactory(): RenderFactory =
                 GraphicsApi.SOFTWARE_FAST -> LinuxSoftwareRedrawer(layer, analytics, properties)
                 else -> LinuxOpenGLRedrawer(layer, analytics, properties)
             }
-            OS.Android, OS.JS, OS.Ios -> throw UnsupportedOperationException("The AWT target doesn't support $hostOs")
+            OS.Android, OS.JS, OS.Ios, OS.Unknown -> throw UnsupportedOperationException("The AWT target doesn't support $hostOs")
         }
     }
 

skiko/src/awtMain/kotlin/org/jetbrains/skiko/PlatformOperations.kt

@@ -125,7 +125,7 @@ internal val platformOperations: PlatformOperations by lazy {
             }
         }
         OS.Android -> TODO()
-        OS.JS, OS.Ios -> {
+        OS.JS, OS.Ios, OS.Unknown -> {
             TODO("Commonize me")
         }
     }

skiko/src/commonMain/kotlin/org/jetbrains/skiko/OsArch.kt

@@ -6,7 +6,10 @@ enum class OS(val id: String) {
     Windows("windows"),
     MacOS("macos"),
     Ios("ios"),
-    JS("js")
+
+    @Deprecated("JS is invalid host OS name. Consider using enum KotlinBackend to detect JS.")
+    JS("js"),
+    Unknown("unknown")
     ;
 
     val isLinux
@@ -22,14 +25,19 @@ enum class OS(val id: String) {
 enum class Arch(val id: String) {
     X64("x64"),
     Arm64("arm64"),
+    @Deprecated("JS is not valid Arch value")
     JS("js"),
-    WASM("wasm")
+    @Deprecated("WASM is not valid Arch value")
+    WASM("wasm"),
+    Unknown("unknown"),
+    ;
 }
 
 enum class KotlinBackend(val id: String) {
     JVM("jvm"),
     JS("js"),
     Native("native"),
+    WASM("wasm"),
     ;
 
     fun isNotJs() = this != JS

skiko/src/jsMain/kotlin/org/jetbrains/skiko/OsArch.js.kt

 package org.jetbrains.skiko
 
-actual val hostOs: OS = OS.JS
+import kotlinx.browser.window
 
-actual val hostArch: Arch = Arch.JS
+actual val hostOs: OS = detectHostOs()
+
+actual val hostArch: Arch = Arch.Unknown
 
 actual val hostId by lazy {
     "${hostOs.id}-${hostArch.id}"
 }
 
 actual val kotlinBackend: KotlinBackend
-    get() = KotlinBackend.JS
\ No newline at end of file
+    get() = KotlinBackend.JS
+
+/**
+ * A string identifying the platform on which the user's browser is running; for example:
+ * "MacIntel", "Win32", "Linux x86_64", "Linux x86_64".
+ * See https://developer.mozilla.org/en-US/docs/Web/API/Navigator/platform - deprecated
+ *
+ * A string containing the platform brand. For example, "Windows".
+ * See https://developer.mozilla.org/en-US/docs/Web/API/NavigatorUAData/platform - new API,
+ * but not supported in all browsers
+ */
+private fun getNavigatorInfo(): String =
+    js("navigator.userAgentData ? navigator.userAgentData.platform : navigator.platform") as String
+
+
+/**
+ * In a browser, user platform can be obtained from different places:
+ * - we attempt to use not-deprecated but experimental option first (not available in all browsers)
+ * - then we attempt to use a deprecated option
+ * - if both above return an empty string, we attempt to get `Platform` from `userAgent`
+ *
+ * Note: a client can spoof these values, so it's okay only for non-critical use cases.
+ */
+internal fun detectHostOs(): OS {
+    val platformInfo = getNavigatorInfo().takeIf {
+        it.isNotEmpty()
+    } ?: window.navigator.userAgent
+
+    return when {
+        platformInfo.contains("Android", true) -> OS.Android
+        platformInfo.contains("iPhone", true) -> OS.Ios
+        platformInfo.contains("iOS", true) -> OS.Ios
+        platformInfo.contains("iPad", true) -> OS.Ios
+        platformInfo.contains("Linux", true) -> OS.Linux
+        platformInfo.contains("Mac", true) -> OS.MacOS
+        platformInfo.contains("Win", true) -> OS.Windows
+        else -> OS.Unknown
+    }
+}
\ No newline at end of file

skiko/src/jsTest/kotlin/org/jetbrains/skiko/HostOsTest.kt

+package org.jetbrains.skiko.tests.org.jetbrains.skiko
+
+import org.jetbrains.skiko.OS
+import org.jetbrains.skiko.detectHostOs
+import org.jetbrains.skiko.hostOs
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+class HostOsTest {
+    @Test
+    fun canGetHostOs() {
+        assertNotEquals(OS.JS, hostOs)
+    }
+
+    @Test
+    fun canGetLinux() {
+        spoofUserAgentData("linux")
+        assertEquals(OS.Linux, detectHostOs())
+    }
+
+    @Test
+    fun canGetWindows() {
+        spoofUserAgentData("Windows")
+        assertEquals(OS.Windows, detectHostOs())
+    }
+
+    @Test
+    fun canGetMacos() {
+        spoofUserAgentData("macos")
+        assertEquals(OS.MacOS, detectHostOs())
+    }
+
+    @Test
+    fun canGetAndroid() {
+        spoofUserAgentData("android")
+        assertEquals(OS.Android, detectHostOs())
+    }
+
+    @Test
+    fun canGetIos() {
+        spoofUserAgentData("ios")
+        assertEquals(OS.Ios, detectHostOs())
+    }
+
+
+    @Test
+    fun fallbackToUnknown() {
+        spoofUserAgentData("somerandomedata")
+        assertEquals(OS.Unknown, detectHostOs())
+    }
+}
+
+private fun spoofUserAgentData(newValue: String) =
+    js("""navigator.__defineGetter__('userAgentData', function () { return { platform:newValue }; });""")
+

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkikoProperties.kt

@@ -70,7 +70,7 @@ object SkikoProperties {
             OS.Linux -> return GraphicsApi.OPENGL
             OS.Windows -> return GraphicsApi.DIRECT3D
             OS.Android -> return GraphicsApi.OPENGL
-            OS.JS, OS.Ios -> TODO("commonize me")
+            OS.JS, OS.Ios, OS.Unknown -> TODO("commonize me")
         }
     }
 
@@ -84,7 +84,7 @@ object SkikoProperties {
                 else -> listOf(GraphicsApi.DIRECT3D, GraphicsApi.OPENGL, GraphicsApi.SOFTWARE_FAST, GraphicsApi.SOFTWARE_COMPAT)
             }
             OS.Android -> return listOf(GraphicsApi.OPENGL)
-            OS.JS, OS.Ios -> TODO("commonize me")
+            OS.JS, OS.Ios, OS.Unknown -> TODO("commonize me")
         }
 
         val indexOfInitialApi = fallbackApis.indexOf(initialApi)