ShellFunctions.java revision 1764:b8634c8d947a 
1/*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.nashorn.tools;
27
28import static jdk.nashorn.internal.lookup.Lookup.MH;
29import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
30
31import java.io.BufferedReader;
32import java.io.IOException;
33import java.io.InputStreamReader;
34import java.lang.invoke.MethodHandle;
35import java.lang.invoke.MethodHandles;
36import jdk.nashorn.internal.runtime.JSType;
37import jdk.nashorn.internal.runtime.ScriptingFunctions;
38import jdk.nashorn.internal.objects.Global;
39
40/**
41 * Global functions supported only in shell interactive mode.
42 */
43public final class ShellFunctions {
44
45    /** Handle to implementation of {@link ShellFunctions#input} - Nashorn extension */
46    public static final MethodHandle INPUT = findOwnMH("input", Object.class, Object.class, Object.class, Object.class);
47
48    /** Handle to implementation of {@link ShellFunctions#evalinput} - Nashorn extension */
49    public static final MethodHandle EVALINPUT = findOwnMH("evalinput",     Object.class, Object.class, Object.class, Object.class);
50
51    private ShellFunctions() {
52    }
53
54    /**
55     * Nashorn extension: global.input (shell-interactive-mode-only)
56     * Read one or more lines of input from the standard input till the
57     * given end marker is seen in standard input.
58     *
59     * @param self   self reference
60     * @param endMarker String used as end marker for input
61     * @param prompt String used as input prompt
62     *
63     * @return line that was read
64     *
65     * @throws IOException if an exception occurs
66     */
67    public static Object input(final Object self, final Object endMarker, final Object prompt) throws IOException {
68        final String endMarkerStr = (endMarker != UNDEFINED)? JSType.toString(endMarker) : "";
69        final String promptStr = (prompt != UNDEFINED)? JSType.toString(prompt)  : ">> ";
70        final StringBuilder buf = new StringBuilder();
71        while (true) {
72            final String line = ScriptingFunctions.readLine(promptStr);
73            if (line == null || line.equals(endMarkerStr)) {
74                break;
75            }
76            buf.append(line);
77            buf.append('\n');
78        }
79        return buf.toString();
80    }
81
82    /**
83     * Nashorn extension: Reads zero or more lines from standard input and
84     * evaluates the concatenated string as code
85     *
86     * @param self self reference
87     * @param endMarker String used as end marker for input
88     * @param prompt String used as input prompt
89     *
90     * @return output from evaluating the script
91     *
92     * @throws IOException if an exception occurs
93     */
94    public static Object evalinput(final Object self, final Object endMarker, final Object prompt) throws IOException {
95        return Global.eval(self, input(self, endMarker, prompt));
96    }
97
98    private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
99        return MH.findStatic(MethodHandles.lookup(), ShellFunctions.class, name, MH.type(rtype, types));
100    }
101}
102