Basic filesystems support for Wasm: reuse JS implementation for wasmJs target (#256)

* Split Wasm source sets
* Supported filesystem for wasmJs target (`node:fs` along with a few related packages is required).

Author: fzhinkin

build-logic/src/main/kotlin/kotlinx/io/conventions/kotlinx-io-multiplatform.gradle.kts

@@ -94,6 +94,8 @@ kotlin {
         createSourceSet("linuxTest", parent = unixTest, children = linuxTargets())
         createSourceSet("androidMain", parent = unixMain, children = androidTargets())
         createSourceSet("androidTest", parent = unixTest, children = androidTargets())
+        createSourceSet("nodeFilesystemSharedMain", parent = commonMain.get(), children = nodeTargets())
+        createSourceSet("nodeFilesystemSharedTest", parent = commonTest.get(), children = nodeTargets())
         createSourceSet("wasmMain", parent = commonMain.get(), children = wasmTargets())
         createSourceSet("wasmTest", parent = commonTest.get(), children = wasmTargets())
     }
@@ -200,6 +202,8 @@ fun androidTargets() = listOf(
 
 fun wasmTargets() = listOf("wasmJs", "wasmWasi")
 
+fun nodeTargets() = listOf("js", "wasmJs")
+
 rootProject.the<NodeJsRootExtension>().apply {
     nodeVersion = "21.0.0-v8-canary202310177990572111"
     nodeDownloadBaseUrl = "https://nodejs.org/download/v8-canary"

core/build.gradle.kts

@@ -43,11 +43,6 @@ kotlin {
         }
     }
 
-    @OptIn(org.jetbrains.kotlin.gradle.targets.js.dsl.ExperimentalWasmDsl::class)
-    wasmJs {
-        filterSmokeTests()
-    }
-
     @OptIn(org.jetbrains.kotlin.gradle.targets.js.dsl.ExperimentalWasmDsl::class)
     wasmWasi {
         filterSmokeTests()

core/js/src/-PlatfromJs.kt

@@ -21,3 +21,18 @@ public actual open class IOException actual constructor(
 public actual open class EOFException actual constructor(message: String?) : IOException(message) {
     public actual constructor() : this(null)
 }
+
+@Suppress("ACTUAL_WITHOUT_EXPECT")
+internal actual typealias CommonJsModule = JsModule
+
+@Suppress("ACTUAL_WITHOUT_EXPECT")
+internal actual typealias CommonJsNonModule = JsNonModule
+
+internal actual fun withCaughtException(block: () -> Unit): Throwable? {
+    try {
+        block()
+        return null
+    } catch (t: Throwable) {
+        return t
+    }
+}

core/js/src/imports.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2024 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
+ */
+
+package kotlinx.io
+
+// The source set is shared by js and wasmJs targets that don't have a single common JS-source set.
+// As a result, JsModule and JsNonModule annotations are unavailable. To overcome that issue,
+// the following expects are declared in this module and actualized in the leaf source sets.
+
+/**
+ * Actualized with JsModule on both JS and WasmJs.
+ */
+@Target(AnnotationTarget.FILE)
+internal expect annotation class CommonJsModule(val import: String)
+
+/**
+ * Actualized with JsNonModule on JS, left "empty" on WasmJs.
+ */
+@Target(AnnotationTarget.FILE)
+internal expect annotation class CommonJsNonModule()

core/js/test/utils.kt

@@ -5,31 +5,35 @@
 
 package kotlinx.io.files
 
-import kotlinx.io.*
+import kotlinx.io.IOException
+import kotlinx.io.RawSink
+import kotlinx.io.RawSource
+import kotlinx.io.node.fs.*
+import kotlinx.io.node.os.platform
+import kotlinx.io.node.os.tmpdir
+import kotlinx.io.withCaughtException
 
 public actual val SystemFileSystem: FileSystem = object : SystemFileSystemImpl() {
     override fun exists(path: Path): Boolean {
-        check(fs !== null) { "Module 'fs' was not found" }
-        return fs.existsSync(path.path) as Boolean
+        return existsSync(path.path)
     }
 
     override fun delete(path: Path, mustExist: Boolean) {
-        check(fs !== null) { "Module 'fs' was not found" }
         if (!exists(path)) {
             if (mustExist) {
-                throw FileNotFoundException("File does not exist: ${path.path}")
+                throw FileNotFoundException("File does not exist: $path")
             }
             return
         }
-        try {
-            val stats = fs.statSync(path.path)
-            if (stats.isDirectory() as Boolean) {
-                fs.rmdirSync(path.path)
+        withCaughtException {
+            val stats = statSync(path.path) ?: throw FileNotFoundException("File does not exist: $path")
+            if (stats.isDirectory()) {
+                rmdirSync(path.path)
             } else {
-                fs.rmSync(path.path)
+                rmSync(path.path)
             }
-        } catch (t: Throwable) {
-            throw IOException("Delete failed for $path", t)
+        }?.also {
+            throw IOException("Delete failed for $path", it)
         }
     }
 
@@ -52,65 +56,60 @@ public actual val SystemFileSystem: FileSystem = object : SystemFileSystemImpl()
             p = p.parent
         }
         parts.asReversed().forEach {
-            fs.mkdirSync(it)
+            mkdirSync(it)
         }
     }
 
     override fun atomicMove(source: Path, destination: Path) {
-        check(fs !== null) { "Module 'fs' was not found" }
         if (!exists(source)) {
             throw FileNotFoundException("Source does not exist: ${source.path}")
         }
-        try {
-            fs.renameSync(source.path, destination.path)
-        } catch (t: Throwable) {
-            throw IOException("Move failed from $source to $destination", t)
+        withCaughtException {
+            renameSync(source.path, destination.path)
+        }?.also {
+            throw IOException("Move failed from $source to $destination", it)
         }
     }
 
     override fun metadataOrNull(path: Path): FileMetadata? {
-        check(fs !== null) { "Module 'fs' was not found" }
-        return try {
-            val stat = fs.statSync(path.path)
-            val mode = stat.mode as Int
-            val isFile =  (mode and fs.constants.S_IFMT as Int) == fs.constants.S_IFREG
-            FileMetadata(
+        if (!exists(path)) return null
+        var metadata: FileMetadata? = null
+        withCaughtException {
+            val stat = statSync(path.path) ?: return@withCaughtException
+            val mode = stat.mode
+            val isFile = (mode and constants.S_IFMT) == constants.S_IFREG
+            metadata = FileMetadata(
                 isRegularFile = isFile,
-                isDirectory = (mode and fs.constants.S_IFMT as Int) == fs.constants.S_IFDIR,
-                if (isFile) (stat.size as Int).toLong() else -1L
+                isDirectory = (mode and constants.S_IFMT) == constants.S_IFDIR,
+                if (isFile) stat.size.toLong() else -1L
             )
-        } catch (t: Throwable) {
-            if (exists(path)) throw IOException("Stat failed for $path", t)
-            return null
+        }?.also {
+            throw IOException("Stat failed for $path", it)
         }
+        return metadata
     }
 
     override fun source(path: Path): RawSource {
-        check(fs !== null) { "Module 'fs' was not found" }
         return FileSource(path)
     }
 
     override fun sink(path: Path, append: Boolean): RawSink {
-        check(fs !== null) { "Module 'fs' was not found" }
-        check(buffer !== null) { "Module 'buffer' was not found" }
         return FileSink(path, append)
     }
 
     override fun resolve(path: Path): Path {
-        check(fs !== null) { "Module 'fs' was not found" }
         if (!exists(path)) throw FileNotFoundException(path.path)
-        return Path(fs.realpathSync.native(path.path) as String)
+        return Path(realpathSync.native(path.path))
     }
 }
 
 public actual val SystemTemporaryDirectory: Path
     get() {
-        check(os !== null) { "Module 'os' was not found" }
-        return Path(os.tmpdir() as? String ?: "")
+        return Path(tmpdir() ?: "")
     }
 
 public actual open class FileNotFoundException actual constructor(
     message: String?,
 ) : IOException(message)
 
-internal actual val isWindows = os.platform() == "win32"
+internal actual val isWindows = platform() == "win32"