1 /*
2 * Copyright (c) 2010, 2013, 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 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 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 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
26 package jdk.nashorn.internal.runtime;
27
28 import java.util.HashSet;
29 import java.util.Set;
30
31 /**
32 * This class provides support for external debuggers. Its primary purpose is
33 * is to simplify the debugger tasks and provide better performance.
34 */
35 final class DebuggerSupport {
36 /**
37 * Hook to force the loading of the DebuggerSupport class so that it is
38 * available to external debuggers.
39 */
40 static boolean FORCELOAD = true;
41
42 static {
43 /**
44 * Hook to force the loading of the DebuggerValueDesc class so that it is
45 * available to external debuggers.
46 */
47 @SuppressWarnings("unused")
48 DebuggerValueDesc forceLoad = new DebuggerValueDesc(null, false, null, null);
49 }
50
51 /** This class is used to send a bulk description of a value. */
52 static class DebuggerValueDesc {
53 /** Property key (or index) or field name. */
54 final String key;
55
56 /** If the value is expandable. */
57 final boolean expandable;
58
59 /** Property or field value as object. */
60 final Object valueAsObject;
61
62 /** Property or field value as string. */
63 final String valueAsString;
64
65 DebuggerValueDesc(final String key, final boolean expandable, final Object valueAsObject, final String valueAsString) {
66 this.key = key;
67 this.expandable = expandable;
68 this.valueAsObject = valueAsObject;
69 this.valueAsString = valueAsString;
70 }
71 }
72
73 /**
74 * Return the current context global.
75 * @return context global.
76 */
77 static Object getGlobal() {
78 return Context.getGlobalTrusted();
79 }
80
81 /**
82 * Call eval on the current global.
83 * @param scope Scope to use.
84 * @param self Receiver to use.
85 * @param string String to evaluate.
86 * @param returnException true if exceptions are to be returned.
87 * @return Result of eval as string, or, an exception or null depending on returnException.
88 */
89 static Object eval(final ScriptObject scope, final Object self, final String string, final boolean returnException) {
90 final ScriptObject global = Context.getGlobalTrusted();
91 final ScriptObject initialScope = scope != null ? scope : global;
92 final Object callThis = self != null ? self : global;
93 final Context context = global.getContext();
94
95 try {
96 return context.eval(initialScope, string, callThis, ScriptRuntime.UNDEFINED, false);
97 } catch (Throwable ex) {
98 return returnException ? ex : null;
99 }
100 }
101
102 /**
103 * This method returns a bulk description of an object's properties.
104 * @param object Script object to be displayed by the debugger.
105 * @param all true if to include non-enumerable values.
106 * @return An array of DebuggerValueDesc.
107 */
108 static DebuggerValueDesc[] valueInfos(final Object object, final boolean all) {
109 assert object instanceof ScriptObject;
110 return getDebuggerValueDescs((ScriptObject)object, all, new HashSet<>());
111 }
112
113 /**
114 * This method returns a debugger description of the value.
115 * @param name Name of value (property name).
116 * @param value Data value.
117 * @param all true if to include non-enumerable values.
118 * @return A DebuggerValueDesc.
119 */
120 static DebuggerValueDesc valueInfo(final String name, final Object value, final boolean all) {
121 return valueInfo(name, value, all, new HashSet<>());
122 }
123
124 /**
125 * This method returns a debugger description of the value.
126 * @param name Name of value (property name).
127 * @param value Data value.
128 * @param all true if to include non-enumerable values.
129 * @param duplicates Duplication set to avoid cycles.
130 * @return A DebuggerValueDesc.
131 */
132 private static DebuggerValueDesc valueInfo(final String name, final Object value, final boolean all, final Set<Object> duplicates) {
133 if (value instanceof ScriptObject && !(value instanceof ScriptFunction)) {
134 final ScriptObject object = (ScriptObject)value;
135 return new DebuggerValueDesc(name, !object.isEmpty(), value, objectAsString(object, all, duplicates));
136 }
137 return new DebuggerValueDesc(name, false, value, valueAsString(value));
138 }
139
140 /**
141 * Generate the descriptions for an object's properties.
142 * @param object Object to introspect.
143 * @param all true if to include non-enumerable values.
144 * @param duplicates Duplication set to avoid cycles.
145 * @return An array of DebuggerValueDesc.
146 */
147 private static DebuggerValueDesc[] getDebuggerValueDescs(final ScriptObject object, final boolean all, final Set<Object> duplicates) {
148 if (duplicates.contains(object)) {
149 return null;
150 }
151
152 duplicates.add(object);
153
154 final String[] keys = object.getOwnKeys(all);
155 final DebuggerValueDesc[] descs = new DebuggerValueDesc[keys.length];
156
157 for (int i = 0; i < keys.length; i++) {
158 final String key = keys[i];
159 descs[i] = valueInfo(key, object.get(key), all, duplicates);
160 }
161
162 duplicates.remove(object);
163
164 return descs;
165 }
166
167 /**
168 * Generate a string representation of a Script object.
169 * @param object Script object to represent.
170 * @param all true if to include non-enumerable values.
171 * @param duplicates Duplication set to avoid cycles.
172 * @return String representation.
173 */
174 private static String objectAsString(final ScriptObject object, final boolean all, final Set<Object> duplicates) {
175 final StringBuilder sb = new StringBuilder();
176
177 if (ScriptObject.isArray(object)) {
178 sb.append('[');
179 final long length = object.getLong("length");
180
181 for (long i = 0; i < length; i++) {
182 if (object.has(i)) {
183 final Object valueAsObject = object.get(i);
184 final boolean isUndefined = JSType.of(valueAsObject) == JSType.UNDEFINED;
185
186 if (isUndefined) {
187 if (i != 0) {
188 sb.append(",");
189 }
190 } else {
191 if (i != 0) {
192 sb.append(", ");
193 }
194
195 if (valueAsObject instanceof ScriptObject && !(valueAsObject instanceof ScriptFunction)) {
196 final String objectString = objectAsString((ScriptObject)valueAsObject, all, duplicates);
197 sb.append(objectString != null ? objectString : "{...}");
198 } else {
199 sb.append(valueAsString(valueAsObject));
200 }
201 }
202 } else {
203 if (i != 0) {
204 sb.append(',');
205 }
206 }
207 }
208
209 sb.append(']');
210 } else {
211 sb.append('{');
212 final DebuggerValueDesc[] descs = getDebuggerValueDescs(object, all, duplicates);
213
214 if (descs != null) {
215 for (int i = 0; i < descs.length; i++) {
216 if (i != 0) {
217 sb.append(", ");
218 }
219
220 final String valueAsString = descs[i].valueAsString;
221 sb.append(descs[i].key);
222 sb.append(": ");
223 sb.append(valueAsString);
224 }
225 }
226
227 sb.append('}');
228 }
229
230 return sb.toString();
231 }
232
233 /**
234 * This method returns a string representation of a value.
235 * @param value Arbitrary value to be displayed by the debugger.
236 * @return A string representation of the value or an array of DebuggerValueDesc.
237 */
238 private static String valueAsString(final Object value) {
239 final JSType type = JSType.of(value);
240
241 switch (type) {
242 case BOOLEAN:
243 return value.toString();
244
245 case STRING:
246 return escape(value.toString());
247
248 case NUMBER:
249 return JSType.toString(((Number)value).doubleValue());
250
251 case NULL:
252 return "null";
253
254 case UNDEFINED:
255 return "undefined";
256
257 case OBJECT:
258 return ScriptRuntime.safeToString(value);
259
260 case FUNCTION:
261 if (value instanceof ScriptFunction) {
262 return ((ScriptFunction)value).toSource();
263 }
264 return value.toString();
265
266 default:
267 return value.toString();
268 }
269 }
270
271 /**
272 * Escape a string into a form that can be parsed by JavaScript.
273 * @param value String to be escaped.
274 * @return Escaped string.
275 */
276 private static String escape(final String value) {
277 final StringBuilder sb = new StringBuilder();
278
279 sb.append("\"");
280
281 for (final char ch : value.toCharArray()) {
282 switch (ch) {
283 case '\\':
284 sb.append("\\\\");
285 break;
286 case '"':
287 sb.append("\\\"");
288 break;
289 case '\'':
290 sb.append("\\\'");
291 break;
292 case '\b':
293 sb.append("\\b");
294 break;
295 case '\f':
296 sb.append("\\f");
297 break;
298 case '\n':
299 sb.append("\\n");
300 break;
301 case '\r':
302 sb.append("\\r");
303 break;
304 case '\t':
305 sb.append("\\t");
306 break;
307 default:
308 if (ch < ' ' || ch >= 0xFF) {
309 sb.append("\\u");
310
311 final String hex = Integer.toHexString(ch);
312 for (int i = hex.length(); i < 4; i++) {
313 sb.append('0');
314 }
315 sb.append(hex);
316 } else {
317 sb.append(ch);
318 }
319
320 break;
321 }
322 }
323
324 sb.append("\"");
325
326 return sb.toString();
327 }
328 }
329
330