Draft of WASI support

.gitignore

@@ -28,4 +28,4 @@ target
 !.idea/copyright
 !.idea/checkstyle-idea.xml
 
-dependency-reduced-pom.xml
+dependency-reduced-pom.xml

classlib/src/main/java/org/teavm/classlib/fs/VirtualFileSystemProvider.java

@@ -18,13 +18,16 @@
 import org.teavm.classlib.PlatformDetector;
 import org.teavm.classlib.fs.c.CFileSystem;
 import org.teavm.classlib.fs.memory.InMemoryVirtualFileSystem;
+import org.teavm.classlib.fs.wasi.WasiFileSystem;
 
 public final class VirtualFileSystemProvider {
     private static VirtualFileSystem instance;
 
     static {
         if (PlatformDetector.isC()) {
             instance = new CFileSystem();
+        } else if (PlatformDetector.isWebAssembly()) {
+            instance = new WasiFileSystem();
         } else {
             instance = new InMemoryVirtualFileSystem();
         }

classlib/src/main/java/org/teavm/classlib/fs/wasi/WasiFileSystem.java

@@ -0,0 +1,41 @@
+/*
+ *  Copyright 2022 TeaVM Contributors.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.classlib.fs.wasi;
+
+import org.teavm.classlib.fs.VirtualFile;
+import org.teavm.classlib.fs.VirtualFileSystem;
+
+public class WasiFileSystem implements VirtualFileSystem {
+    @Override
+    public String getUserDir() {
+        return "/";
+    }
+
+    @Override
+    public VirtualFile getFile(String path) {
+        return new WasiVirtualFile(path);
+    }
+
+    @Override
+    public boolean isWindows() {
+        return false;
+    }
+
+    @Override
+    public String canonicalize(String path) {
+        return path;
+    }
+}