org.graalvm.launcher.MultiLanguageShell Maven / Gradle / Ivy
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package org.graalvm.launcher;
import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.graalvm.polyglot.Context;
import org.graalvm.polyglot.Language;
import org.graalvm.polyglot.PolyglotException;
import org.graalvm.polyglot.PolyglotException.StackFrame;
import org.graalvm.polyglot.Source;
import org.graalvm.shadowed.org.jline.keymap.KeyMap;
import org.graalvm.shadowed.org.jline.reader.EndOfFileException;
import org.graalvm.shadowed.org.jline.reader.History;
import org.graalvm.shadowed.org.jline.reader.LineReader;
import org.graalvm.shadowed.org.jline.reader.LineReaderBuilder;
import org.graalvm.shadowed.org.jline.reader.Reference;
import org.graalvm.shadowed.org.jline.reader.UserInterruptException;
import org.graalvm.shadowed.org.jline.reader.impl.history.DefaultHistory;
import org.graalvm.shadowed.org.jline.terminal.Terminal;
class MultiLanguageShell implements Closeable {
private static final String WIDGET_NAME = "CHANGE_LANGUAGE_WIDGET";
private final Map histories = new HashMap<>();
private final Context context;
private final String startLanguage;
private final List languages;
private final Map prompts;
private final StringBuilder promptsString = new StringBuilder();
private final Terminal terminal;
private LineReader reader;
private Language currentLanguage;
private boolean verboseErrors = false;
private String input = "";
MultiLanguageShell(Context context, String defaultStartLanguage, Terminal terminal) {
this.context = context;
this.languages = languages();
this.prompts = prompts();
this.terminal = terminal;
this.startLanguage = defaultStartLanguage == null ? languages.get(0).getId() : defaultStartLanguage;
currentLanguage = context.getEngine().getLanguages().get(startLanguage);
if (currentLanguage == null) {
throw new Launcher.AbortException("Error: could not find language '" + startLanguage + "'", 1);
}
resetLineReader();
}
private static String createBufferPrompt(String prompt) {
StringBuilder b = new StringBuilder();
for (int i = 0; i < prompt.length() - 2; i++) {
b.append(" ");
}
return b.append("+ ").toString();
}
private static String createPrompt(Language currentLanguage) {
return String.format("%s> ", currentLanguage.getId());
}
public int runRepl() {
printHeader();
for (;;) {
try {
input += reader.readLine(prompt()) + "\n";
if (handleBuiltins() || eval()) {
reader.getHistory().add(input);
input = "";
}
} catch (ChangeLanguageException e) {
handle(e);
} catch (PolyglotException e) {
handle(e);
if (e.isExit()) {
return e.getExitStatus();
}
} catch (UserInterruptException | EndOfFileException e) {
// interrupted by ctrl-c or ctrl-d
break;
} catch (Throwable e) {
handleInternal(e);
}
}
return 0;
}
private String prompt() {
final String prompt = createPrompt(currentLanguage);
return input.equals("") ? prompt : createBufferPrompt(prompt);
}
private boolean eval() throws IOException {
Source source = Source.newBuilder(currentLanguage.getId(), input, "").interactive(true).build();
context.eval(source);
return true;
}
private void handle(ChangeLanguageException e) {
histories.put(currentLanguage, reader.getHistory());
currentLanguage = e.getLanguage() == null ? languages.get((languages.indexOf(currentLanguage) + 1) % languages.size()) : e.getLanguage();
resetLineReader();
input = "";
}
private void handleInternal(Throwable e) {
println("Internal error occurred: " + e.toString());
if (verboseErrors) {
e.printStackTrace(terminal.writer());
} else {
println("Run with --verbose to see the full stack trace.");
}
}
private void handle(PolyglotException e) {
if (e.isIncompleteSource()) {
return;
}
input = "";
if (e.isInternalError()) {
handleInternal(e);
} else if (e.isCancelled()) {
println("Execution got cancelled.");
} else if (e.isSyntaxError()) {
println(e.getMessage());
} else {
List trace = new ArrayList<>();
for (StackFrame stackFrame : e.getPolyglotStackTrace()) {
trace.add(stackFrame);
}
// remove trailing host frames
for (int i = trace.size() - 1; i >= 0; i--) {
if (trace.get(i).isHostFrame()) {
trace.remove(i);
} else {
break;
}
}
if (e.isHostException()) {
println(e.asHostException().toString());
} else {
println(String.valueOf(e.getMessage()));
}
// no need to print stack traces with single entry
if (trace.size() > 1) {
for (StackFrame stackFrame : trace) {
print(" at ");
println(stackFrame.toString());
}
}
}
}
private boolean handleBuiltins() {
final String trimmedInput = input.trim();
if (trimmedInput.equals("")) {
return true;
}
if (trimmedInput.equals("-usage")) {
printUsage(true);
return true;
}
if (trimmedInput.equals("-verboseErrors")) {
verboseErrors = !verboseErrors;
if (verboseErrors) {
println("Verbose errors is now on.");
} else {
println("Verbose errors is now off.");
}
return true;
}
if (prompts.containsKey(trimmedInput)) {
throw new ChangeLanguageException(prompts.get(trimmedInput));
}
return false;
}
private void printHeader() {
println("GraalVM MultiLanguage Shell " + context.getEngine().getVersion());
println("Copyright (c) 2013-2021, Oracle and/or its affiliates");
for (Language language : languages) {
println(" " + language.getName() + " version " + language.getVersion());
}
printUsage(false);
}
private void println(String s) {
terminal.writer().println(s);
}
private void print(String s) {
terminal.writer().print(s);
}
private void resetLineReader() {
reader = LineReaderBuilder.builder().terminal(terminal).appName("GraalVM MultiLanguage Shell " + context.getEngine().getVersion()).history(
histories.computeIfAbsent(currentLanguage, language -> new DefaultHistory())).build();
for (String s : reader.getKeyMaps().keySet()) {
reader.getKeyMaps().get(s).bind(new Reference(WIDGET_NAME), KeyMap.ctrl('n'));
reader.getWidgets().put(WIDGET_NAME, () -> {
throw new ChangeLanguageException(null);
});
}
}
private Map prompts() {
Map p = new HashMap<>();
for (Language language : languages) {
String prompt = createPrompt(language).trim();
promptsString.append(prompt).append(" ");
p.put(prompt, language);
}
return p;
}
private List languages() {
List langs = new ArrayList<>();
Set uniqueValues = new HashSet<>();
for (Language language : context.getEngine().getLanguages().values()) {
if (language.isInteractive()) {
if (uniqueValues.add(language)) {
langs.add(language);
}
}
}
if (langs.isEmpty()) {
throw new Launcher.AbortException("Error: No Graal languages installed. Exiting shell.", 1);
}
langs.sort(Comparator.comparing(Language::getName));
return langs;
}
private void printUsage(boolean showCommands) {
if (showCommands) {
println("Commands:");
println(" -usage to show this list.");
println(" -verboseErrors to toggle verbose error messages (default off).");
println(" " + promptsString + " to switch to a language.");
} else {
println("Usage: ");
println(" Use Ctrl+n to switch language and Ctrl+d to exit.");
println(" Enter -usage to get a list of available commands.");
}
}
@Override
public void close() throws IOException {
terminal.close();
}
@SuppressWarnings("serial")
private static class ChangeLanguageException extends RuntimeException {
private final Language language;
ChangeLanguageException(Language language) {
this.language = language;
}
public Language getLanguage() {
return language;
}
@SuppressWarnings("sync-override")
@Override
public final Throwable fillInStackTrace() {
return this;
}
}
}
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