classlib: optimize console output in JS backend

classlib/src/main/java/org/teavm/classlib/impl/console/JSStderrPrintStream.java

@@ -0,0 +1,28 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  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.impl.console;
+
+import org.teavm.jso.JSBody;
+
+public class JSStderrPrintStream extends JsConsolePrintStream {
+    @Override
+    public void print(String s) {
+        writeJs(s);
+    }
+
+    @JSBody(params = "b", script = "$rt_putStderr(b);")
+    private static native void writeJs(String s);
+}

classlib/src/main/java/org/teavm/classlib/impl/console/JSStdoutPrintStream.java

@@ -0,0 +1,28 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  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.impl.console;
+
+import org.teavm.jso.JSBody;
+
+public class JSStdoutPrintStream extends JsConsolePrintStream {
+    @Override
+    public void print(String s) {
+        writeJs(s);
+    }
+
+    @JSBody(params = "b", script = "$rt_putStdout(b);")
+    private static native void writeJs(String s);
+}

classlib/src/main/java/org/teavm/classlib/impl/console/JsConsolePrintStream.java

@@ -0,0 +1,196 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  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.impl.console;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.CodingErrorAction;
+import java.nio.charset.StandardCharsets;
+import java.util.Objects;
+
+public abstract class JsConsolePrintStream extends PrintStream {
+    private ByteEncoder byteEncoder;
+    private Runnable flushAction;
+
+    public JsConsolePrintStream() {
+        super(new ByteArrayOutputStream());
+    }
+
+    @Override
+    public void println(String s) {
+        print(s);
+        print("\n");
+    }
+
+    @Override
+    public void print(int i) {
+        print(Integer.toString(i));
+    }
+
+    @Override
+    public void print(char c) {
+        print(Character.toString(c));
+    }
+
+    @Override
+    public void print(long l) {
+        print(Long.toString(l));
+    }
+
+    @Override
+    public void print(double d) {
+        super.print(d);
+    }
+
+    @Override
+    public void print(Object s) {
+        print(Objects.toString(s));
+    }
+
+    @Override
+    public void print(char[] s) {
+        print(new String(s));
+    }
+
+    @Override
+    public void println() {
+        print("\n");
+    }
+
+    @Override
+    public void println(int i) {
+        println(Integer.toString(i));
+    }
+
+    @Override
+    public void println(char c) {
+        println(Character.toString(c));
+    }
+
+    @Override
+    public void println(long l) {
+        println(Long.toString(l));
+    }
+
+    @Override
+    public void println(float d) {
+        println(Float.toString(d));
+    }
+
+    @Override
+    public void println(double d) {
+        println(Double.toString(d));
+    }
+
+    @Override
+    public void println(boolean b) {
+        println(Boolean.toString(b));
+    }
+
+    @Override
+    public void println(Object s) {
+        println(Objects.toString(s));
+    }
+
+    @Override
+    public void write(int b) {
+        ensureByteEncoder().write(b);
+    }
+
+    @Override
+    public void write(byte[] b, int off, int len) {
+        ensureByteEncoder().write(b, off, len);
+    }
+
+    @Override
+    public void flush() {
+        if (flushAction != null) {
+            flushAction = null;
+            flushAction.run();
+        }
+    }
+
+    private ByteEncoder ensureByteEncoder() {
+        if (byteEncoder == null) {
+            byteEncoder = new ByteEncoder();
+        }
+        return byteEncoder;
+    }
+
+    @Override
+    public abstract void print(String s);
+
+    private class ByteEncoder {
+        private ByteBuffer buffer = ByteBuffer.wrap(new byte[32]);
+        private char[] outChars = new char[32];
+        private CharBuffer outBuffer = CharBuffer.wrap(outChars);
+        private CharsetDecoder decoder = StandardCharsets.UTF_8
+                .newDecoder()
+                .onMalformedInput(CodingErrorAction.REPLACE)
+                .onUnmappableCharacter(CodingErrorAction.REPLACE);
+
+        void write(int b) {
+            postponeFlush();
+            if (!buffer.hasRemaining()) {
+                output();
+            }
+            buffer.put((byte) b);
+        }
+
+        void write(byte[] b, int off, int len) {
+            postponeFlush();
+            while (len > 0) {
+                var count = Math.min(len, buffer.remaining());
+                buffer.put(b, off, count);
+                len -= count;
+                output();
+            }
+        }
+
+        void postponeFlush() {
+            if (flushAction == null) {
+                flushAction = this::flush;
+            }
+        }
+
+        private void flush() {
+            if (buffer.position() > 0) {
+                output(true);
+            }
+        }
+
+        private void output() {
+            output(false);
+        }
+
+        private void output(boolean endOfInput) {
+            buffer.flip();
+            while (true) {
+                var result = decoder.decode(buffer, outBuffer, endOfInput);
+                print(new String(outChars, 0, outBuffer.position()));
+                outBuffer.rewind();
+                if (result != CoderResult.OVERFLOW) {
+                    break;
+                }
+            }
+            buffer.compact();
+        }
+    }
+}

classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java

@@ -24,6 +24,8 @@ import org.teavm.backend.c.runtime.fs.CFileSystem;
 import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.backend.wasm.runtime.WasmSupport;
 import org.teavm.classlib.PlatformDetector;
+import org.teavm.classlib.impl.console.JSStderrPrintStream;
+import org.teavm.classlib.impl.console.JSStdoutPrintStream;
 import org.teavm.classlib.impl.console.StderrOutputStream;
 import org.teavm.classlib.impl.console.StdoutOutputStream;
 import org.teavm.classlib.java.io.TConsole;
@@ -55,14 +57,22 @@ public final class TSystem extends TObject {
 
     public static TPrintStream out() {
         if (outCache == null) {
-            outCache = new TPrintStream((TOutputStream) (Object) StdoutOutputStream.INSTANCE, false);
+            if (PlatformDetector.isJavaScript()) {
+                outCache = (TPrintStream) (Object) new JSStdoutPrintStream();
+            } else {
+                outCache = new TPrintStream((TOutputStream) (Object) StdoutOutputStream.INSTANCE, false);
+            }
         }
         return outCache;
     }
 
     public static TPrintStream err() {
         if (errCache == null) {
-            errCache = new TPrintStream((TOutputStream) (Object) StderrOutputStream.INSTANCE, false);
+            if (PlatformDetector.isJavaScript()) {
+                errCache = (TPrintStream) (Object) new JSStderrPrintStream();
+            } else {
+                errCache = new TPrintStream((TOutputStream) (Object) StderrOutputStream.INSTANCE, false);
+            }
         }
         return errCache;
     }

core/src/main/resources/org/teavm/backend/javascript/runtime.js

@@ -397,55 +397,30 @@ let $rt_assertNotNaN = value => {
     }
     return value;
 }
-let $rt_createOutputFunction = printFunction => {
+
+let $rt_createOutputFunction = outputFunction => {
     let buffer = "";
-    let utf8Buffer = 0;
+    return msg => {
-    let utf8Remaining = 0;
+        let index = 0;
-
+        while (true) {
-    let putCodePoint = ch =>{
+            let next = msg.indexOf('\n', index);
-        if (ch === 0xA) {
+            if (next < 0) {
-            printFunction(buffer);
+                break;
-            buffer = "";
-        } else if (ch < 0x10000) {
-            buffer += String.fromCharCode(ch);
-        } else {
-            ch = (ch - 0x10000) | 0;
-            let hi = (ch >> 10) + 0xD800;
-            let lo = (ch & 0x3FF) + 0xDC00;
-            buffer += String.fromCharCode(hi, lo);
-        }
-    }
-
-    return ch => {
-        if ((ch & 0x80) === 0) {
-            putCodePoint(ch);
-        } else if ((ch & 0xC0) === 0x80) {
-            if (utf8Buffer > 0) {
-                utf8Remaining <<= 6;
-                utf8Remaining |= ch & 0x3F;
-                if (--utf8Buffer === 0) {
-                    putCodePoint(utf8Remaining);
-                }
             }
-        } else if ((ch & 0xE0) === 0xC0) {
+            outputFunction(buffer + msg.substring(index, next));
-            utf8Remaining = ch & 0x1F;
+            buffer = "";
-            utf8Buffer = 1;
+            index = next + 1;
-        } else if ((ch & 0xF0) === 0xE0) {
-            utf8Remaining = ch & 0x0F;
-            utf8Buffer = 2;
-        } else if ((ch & 0xF8) === 0xF0) {
-            utf8Remaining = ch & 0x07;
-            utf8Buffer = 3;
         }
-    };
+        buffer += msg.substring(index);
+    }
 }
 
 let $rt_putStdout = typeof teavm_globals.$rt_putStdoutCustom === "function"
     ? teavm_globals.$rt_putStdoutCustom
-    : typeof console === "object" ? $rt_createOutputFunction(function(msg) { console.info(msg); }) : function() {};
+    : typeof console === "object" ? $rt_createOutputFunction(msg => console.info(msg)) : () => {};
 let $rt_putStderr = typeof teavm_globals.$rt_putStderrCustom === "function"
     ? teavm_globals.$rt_putStderrCustom
-    : typeof console === "object" ? $rt_createOutputFunction(function(msg) { console.error(msg); }) : function() {};
+    : typeof console === "object" ? $rt_createOutputFunction(msg => console.error(msg)) : () => {};
 
 let $rt_packageData = null;
 let $rt_packages = data => {

samples/stdout-helper/src/main/webapp/teavm/stdout.js

@@ -1,14 +1,18 @@
 let $rt_stdoutBuffer = "";
-function $rt_putStdoutCustom(ch) {
+function $rt_putStdoutCustom(str) {
-    if (ch === 0xA) {
+    let index = 0;
-        var lineElem = document.createElement("div");
+    while (true) {
-        var stdoutElem = document.getElementById("stdout");
+        let next = msg.indexOf('\n', index);
-        lineElem.appendChild(document.createTextNode($rt_stdoutBuffer));
+        if (next < 0) {
+            break;
+        }
+        let line = buffer + msg.substring(index, next);
+        let lineElem = document.createElement("div");
+        let stdoutElem = document.getElementById("stdout");
+        lineElem.appendChild(document.createTextNode(line));
         stdoutElem.appendChild(lineElem);
-        $rt_stdoutBuffer = "";
+        buffer = "";
-        stdoutElem.scrollTop = stdoutElem.scrollHeight;
+        index = next + 1;
-    } else {
-        $rt_stdoutBuffer += String.fromCharCode(ch);
     }
 }
 this.$rt_putStdoutCustom = $rt_putStdoutCustom;

tools/junit/src/main/resources/test-server/frame.js

@@ -188,43 +188,17 @@ let $rt_putStderrCustom = createOutputFunction(msg => {
 
 function createOutputFunction(printFunction) {
     let buffer = "";
-    let utf8Buffer = 0;
+    return msg => {
-    let utf8Remaining = 0;
+        let index = 0;
-
+        while (true) {
-    function putCodePoint(ch) {
+            let next = msg.indexOf('\n', index);
-        if (ch === 0xA) {
+            if (next < 0) {
-            printFunction(buffer);
+                break;
-            buffer = "";
-        } else if (ch < 0x10000) {
-            buffer += String.fromCharCode(ch);
-        } else {
-            ch = (ch - 0x10000) | 0;
-            var hi = (ch >> 10) + 0xD800;
-            var lo = (ch & 0x3FF) + 0xDC00;
-            buffer += String.fromCharCode(hi, lo);
-        }
-    }
-
-    return ch => {
-        if ((ch & 0x80) === 0) {
-            putCodePoint(ch);
-        } else if ((ch & 0xC0) === 0x80) {
-            if (utf8Buffer > 0) {
-                utf8Remaining <<= 6;
-                utf8Remaining |= ch & 0x3F;
-                if (--utf8Buffer === 0) {
-                    putCodePoint(utf8Remaining);
-                }
             }
-        } else if ((ch & 0xE0) === 0xC0) {
+            printFunction(buffer + msg.substring(index, next));
-            utf8Remaining = ch & 0x1F;
+            buffer = "";
-            utf8Buffer = 1;
+            index = next + 1;
-        } else if ((ch & 0xF0) === 0xE0) {
-            utf8Remaining = ch & 0x0F;
-            utf8Buffer = 2;
-        } else if ((ch & 0xF8) === 0xF0) {
-            utf8Remaining = ch & 0x07;
-            utf8Buffer = 3;
         }
-    };
+        buffer += msg.substring(index);
+    }
 }