1 // Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
9 * This class encapsulates a single trap placed on a given node. The
10 * traps for a given property name on a given box are maintained as a
11 * linked list stack, with the most recently placed trap at the head
16 // Static Data //////////////////////////////////////////////////////////////
18 /** a vector of weak references to all instances of Trap; used for retheming */
19 private static Hashtable allTraps = new Hashtable(1000);
21 /** List of properties that cannot be trapped */
22 private static final Hash PROHIBITED = new Hash(120, 3);
25 String[] p = new String[] {
26 "sizetoimage", "shrink", "hshrink", "vshrink", "x", "y", "width", "height",
27 "flex", "align", "invisible", "absolute", "globalx", "globaly",
28 "minwidth", "minheight", "height", "width", "maxwidth", "maxheight",
29 "numchildren", "hpad", "vpad", "doublebuffered", "cursor",
30 "mousex", "mousey", "xwt", "static", "mouseinside", "root", "thisbox", "indexof", "svg"
32 for(int i=0; i<p.length; i++) PROHIBITED.put(p[i], Boolean.TRUE);
35 private static Object dummy = new Object();
38 // Instance Members ////////////////////////////////////////////////////////
40 /** the box on which this trap was placed */
41 private Box trapee = null;
43 /** If this trap was actually placed on a root proxy, this is a reference to the proxy */
46 /** the function for this trap */
47 JS.CompiledFunction f = null;
49 /** the name of the property that this trap was placed on */
50 private String name = null;
52 /** the next trap down the trap stack */
53 private Trap next = null;
55 /** true if this is a read-trap */
56 boolean isreadtrap = false;
58 /** The nodeName of the Template whose script placed the trap. See Template.nodeName for more detail. */
59 private String placerNodeName = null;
61 /** our weak reference in the allTraps Hash */
62 private Weak myWeak = Platform.getWeak(this);
65 // Static Methods //////////////////////////////////////////////////////////////////////////
69 * @param trapee the box to place the trap on
70 * @param name the name of the property to trap on
71 * @param f the function to place as a trap
72 * @param isreadtrap true iff this is a read (double-underscore) trap
73 * @param rp if this trap is being placed via a rootproxy, this is that proxy object.
75 static void addTrap(Box trapee, String name, JS.CompiledFunction f, boolean isreadtrap, JS rp) {
77 if (PROHIBITED.get(name) != null || name.startsWith("xwt_")) {
78 Log.log(Trap.class, "Error: you cannot place traps on special property \"" + name + "\"");
82 // find out what script is currently running
83 JS.CompiledFunction placer = JS.Thread.fromJavaThread(java.lang.Thread.currentThread()).getCurrentCompiledFunction();
84 if (placer == null) { Log.log(Trap.class, "placer is null"); return; }
85 String placerNodeName = placer.getSourceName();
87 // check if this script has already placed a trap on this property
88 if (trapee.traps == null) trapee.traps = new Hash(10, 3);
89 for(Trap t = (Trap)trapee.traps.get(name); t != null; t = t.next) if (t.placerNodeName.equals(placerNodeName)) return;
91 // actually place the trap
93 t.next = (Trap)trapee.traps.get(name);
94 trapee.traps.put(name, t);
97 t.placerNodeName = placerNodeName;
100 t.isreadtrap = isreadtrap;
102 // make sure that the surface knows when we place traps on these two properties (slightly inelegant)
103 if (trapee.surface != null && (name.equals("KeyPressed") || name.equals("KeyReleased"))) {
104 trapee.surface.keywatchers.removeElement(trapee);
105 trapee.surface.keywatchers.addElement(trapee);
109 /** returns the function placed as a trap on property <code>name</code> of box <code>b</code> by the currently-running script */
110 public static Trap getTrap(Box b, String name) {
111 if (b.traps == null) return null;
113 String currentFunctionNodeName = JS.Thread.fromJavaThread(java.lang.Thread.currentThread()).getCurrentCompiledFunction().getSourceName();
114 for(Trap cur = (Trap)b.traps.get(name); cur != null; cur = cur.next)
115 if (cur.placerNodeName.equals(currentFunctionNodeName))
121 /** Called by Rhino's arguments.cascade. Note: cx will be null if this was invoked from perform() rather than from a script. */
122 public static final CascadeFunction cascadeFunction = new CascadeFunction();
123 private static class CascadeFunction extends JS.Callable {
124 CascadeFunction() { setSeal(true); }
125 public Object call(JS.Array args) { return call(args, JS.Thread.fromJavaThread(java.lang.Thread.currentThread()).getCurrentCompiledFunction()); }
126 public Object call(JS.Array args, JS.CompiledFunction currentFunction) {
127 Trap currentTrap = TrapContext.get().currentTrap;
128 if (args.length() != 0) TrapContext.get().putCascadeHappened = true;
129 Trap t = currentTrap.next;
130 // if we've hit the end of the trap stack, just do a put(,,,true)
132 if (args.length() == 0) return currentTrap.trapee.get(currentTrap.name, true);
133 currentTrap.trapee.put(currentTrap.name, args.elementAt(0), true);
136 return t.perform(args);
140 /** called by Rhino's arguments.trapee hack */
141 public static Object currentTrapee() {
142 Trap current = TrapContext.get().currentTrap;
143 if (current == null) return null;
144 else if (current.rp != null) return current.rp;
145 else return current.trapee;
148 /** called by Rhino's arguments.trapname hack */
149 public static String currentTrapname() {
150 Trap current = TrapContext.get().currentTrap;
151 if (current == null) return null;
152 else return current.name;
156 // Instance Methods //////////////////////////////////////////////////////////////////////////
158 private Trap() { allTraps.put(myWeak, dummy); }
160 /** perform this trap -- arg.length == 0 if this is a get; otherwise it contains a single element to be put */
161 public Object perform(JS.Array args) {
162 TrapContext tc = TrapContext.get();
164 // save both thread-locals on the stack and update their values
165 Trap save_currentTrap = tc.currentTrap;
166 tc.currentTrap = this;
168 boolean save_putCascadeHappened = tc.putCascadeHappened;
169 tc.putCascadeHappened = false;
171 // invoke the trap function
173 if (!isreadtrap && args.length() == 0) return cascadeFunction.call(args, f);
176 if (Log.verbose) Log.log(this, "debug: reclaimed a dangling trap on property " + name);
177 Object ret = cascadeFunction.call(args, f);
182 Object ret = f.call(args);
184 // autocascade if required
185 if (args.length() > 0 && !isreadtrap && !tc.putCascadeHappened) cascadeFunction.call(args, f);
190 if (Log.on) Log.log(this, e);
193 // restore the thread-locals
194 tc.putCascadeHappened = save_putCascadeHappened;
195 tc.currentTrap = save_currentTrap;
201 /** removes this trap */
202 public void delete() {
203 for(Trap last = null, cur = (Trap)trapee.traps.get(name); cur != null; last = cur, cur = cur.next) {
204 if (cur != this) continue;
205 else if (last != null) last.next = cur.next;
206 else if (cur.next == null) trapee.traps.remove(name);
207 else trapee.traps.put(name, cur.next);
209 if (trapee.surface != null && !trapee.is_trapped("KeyPressed") && !trapee.is_trapped("KeyReleased"))
210 trapee.surface.keywatchers.removeElement(trapee);
211 allTraps.remove(myWeak);
214 /** per-thread storage for Traps */
215 private static class TrapContext {
217 private static Hash trapContextByThread = new Hash();
218 private TrapContext() { }
220 private boolean putCascadeHappened = false;
221 private Trap currentTrap = null;
222 private int trapDepth = 0;
224 /** returns the TrapContext for the current thread */
225 static TrapContext get() {
226 TrapContext ret = (TrapContext)trapContextByThread.get(java.lang.Thread.currentThread());
228 ret = new TrapContext();
229 trapContextByThread.put(Thread.currentThread(), ret);