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 */
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.Function 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 String placerNodeName = JS.getCurrentFunctionSourceName();
85 // check if this script has already placed a trap on this property
86 if (trapee.traps == null) trapee.traps = new Hash(10, 3);
87 for(Trap t = (Trap)trapee.traps.get(name); t != null; t = t.next) if (t.placerNodeName.equals(placerNodeName)) return;
89 // actually place the trap
91 t.next = (Trap)trapee.traps.get(name);
92 trapee.traps.put(name, t);
95 t.placerNodeName = placerNodeName;
98 t.isreadtrap = isreadtrap;
100 // make sure that the surface knows when we place traps on these two properties (slightly inelegant)
101 if (trapee.surface != null && (name.equals("KeyPressed") || name.equals("KeyReleased"))) {
102 trapee.surface.keywatchers.removeElement(trapee);
103 trapee.surface.keywatchers.addElement(trapee);
107 /** returns the function placed as a trap on property <code>name</code> of box <code>b</code> by the currently-running script */
108 public static Trap getTrap(Box b, String name) {
109 if (b.traps == null) return null;
111 String currentFunctionNodeName = JS.getCurrentFunctionSourceName();
112 for(Trap cur = (Trap)b.traps.get(name); cur != null; cur = cur.next)
113 if (cur.placerNodeName.equals(currentFunctionNodeName))
119 /** Called by Rhino's arguments.cascade. Note: cx will be null if this was invoked from perform() rather than from a script. */
120 public static final CascadeFunction cascadeFunction = new CascadeFunction();
121 private static class CascadeFunction extends JS.Function {
122 CascadeFunction() { setSeal(true); }
123 public Object _call(JS.Array args) { return _call(args, JS.getCurrentFunction()); }
124 public Object _call(JS.Array args, Function currentFunction) {
125 Trap currentTrap = TrapContext.get().currentTrap;
127 if (currentTrap == null || (currentFunction != currentTrap.f)) {
128 if (Log.on) Log.log(this, "attempt to cascade() by a function that was not invoked as a trap at " +
129 currentFunction.getSourceName());
130 if (Log.on) Log.log(this, "currentfunction == " + currentFunction);
131 if (Log.on) Log.log(this, "currentTrap.f == " + currentTrap.f);
135 if (args.length() != 0) TrapContext.get().putCascadeHappened = true;
136 Trap t = currentTrap.next;
137 // if we've hit the end of the trap stack, just do a put(,,,true)
139 if (args.length() == 0) return currentTrap.trapee.get(currentTrap.name, true);
140 currentTrap.trapee.put(currentTrap.name, args.elementAt(0), true);
143 return t.perform(args);
147 /** called by Rhino's arguments.trapee hack */
148 public static Object currentTrapee() {
149 Trap current = TrapContext.get().currentTrap;
150 if (current == null) return null;
151 else if (current.rp != null) return current.rp;
152 else return current.trapee;
155 /** called by Rhino's arguments.trapname hack */
156 public static String currentTrapname() {
157 Trap current = TrapContext.get().currentTrap;
158 if (current == null) return null;
159 else return current.name;
163 // Instance Methods //////////////////////////////////////////////////////////////////////////
165 private Trap() { allTraps.put(myWeak, dummy); }
167 /** perform this trap -- arg.length == 0 if this is a get; otherwise it contains a single element to be put */
168 public Object perform(JS.Array args) {
169 TrapContext tc = TrapContext.get();
171 // save both thread-locals on the stack and update their values
172 Trap save_currentTrap = tc.currentTrap;
173 tc.currentTrap = this;
175 boolean save_putCascadeHappened = tc.putCascadeHappened;
176 tc.putCascadeHappened = false;
178 // invoke the trap function
180 if (!isreadtrap && args.length() == 0) return cascadeFunction._call(args, f);
183 if (Log.verbose) Log.log(this, "debug: reclaimed a dangling trap on property " + name);
184 Object ret = cascadeFunction._call(args, f);
189 Object ret = f._call(args);
191 // autocascade if required
192 if (args.length() > 0 && !isreadtrap && !tc.putCascadeHappened) cascadeFunction._call(args, f);
197 if (Log.on) Log.log(this, e);
200 // restore the thread-locals
201 tc.putCascadeHappened = save_putCascadeHappened;
202 tc.currentTrap = save_currentTrap;
208 /** removes this trap */
209 public void delete() {
210 for(Trap last = null, cur = (Trap)trapee.traps.get(name); cur != null; last = cur, cur = cur.next) {
211 if (cur != this) continue;
212 else if (last != null) last.next = cur.next;
213 else if (cur.next == null) trapee.traps.remove(name);
214 else trapee.traps.put(name, cur.next);
216 if (trapee.surface != null && !trapee.is_trapped("KeyPressed") && !trapee.is_trapped("KeyReleased"))
217 trapee.surface.keywatchers.removeElement(trapee);
218 allTraps.remove(myWeak);
221 /** per-thread storage for Traps */
222 private static class TrapContext {
224 private static Hash trapContextByThread = new Hash();
225 private TrapContext() { }
227 private boolean putCascadeHappened = false;
228 private Trap currentTrap = null;
229 private int trapDepth = 0;
231 /** returns the TrapContext for the current thread */
232 static TrapContext get() {
233 TrapContext ret = (TrapContext)trapContextByThread.get(Thread.currentThread());
235 ret = new TrapContext();
236 trapContextByThread.put(Thread.currentThread(), ret);