Annotation of libwww/Library/src/HTHist.c, revision 2.2
2.1 frystyk 1: /* HTHist.c
2: ** NAVIGATION MANAGER
3: **
2.2 ! frystyk 4: ** (c) COPYRIGHT MIT 1995.
2.1 frystyk 5: ** Please first read the full copyright statement in the file COPYRIGH.
6: */
7:
8: /* Library include files */
9: #include "tcp.h"
10: #include "HTUtils.h"
11: #include "HTHist.h"
12:
13: static HTList * history; /* List of visited anchors */
14:
15:
16: /* Record the jump to an anchor
17: ** ----------------------------
18: */
19:
20: void HTHistory_record
21: ARGS1 (HTAnchor *,destination)
22: {
23: if (destination) {
24: if (! history)
25: history = HTList_new();
26: HTList_addObject (history, destination);
27: }
28: }
29:
30: /* Go back in history (find the last visited node)
31: ** ------------------
32: */
33:
34: BOOL HTHistory_canBacktrack
35: NOARGS
36: {
37: return (HTList_objectAt (history, 1) != NULL);
38: }
39:
40: HTAnchor * HTHistory_backtrack
41: NOARGS /* FIXME: Should we add a `sticky' option ? */
42: {
43: if (HTHistory_canBacktrack())
44: HTList_removeLastObject (history);
45: /* is Home if can't backtrack */
46: return (HTAnchor *) HTList_lastObject (history);
47: }
48:
49:
50: PUBLIC HTAnchor * HTHistory_back ARGS1 (HTAnchor *,cur_anch)
51: {
52: if (HTHistory_canBacktrack()) {
53: int pos = HTList_indexOf(history, cur_anch);
54: return ((HTAnchor *) HTList_objectAt(history, pos + 1));
55: }
56: return NULL; /* to indicate that browser should not redraw */
57: }
58:
59:
60: PUBLIC HTAnchor * HTHistory_forward ARGS1 (HTAnchor *,cur_anch)
61: {
62: int pos = HTList_indexOf(history, cur_anch);
63: if (pos <= 0)
64: return NULL;
65: else
66: return ((HTAnchor *) HTList_objectAt(history, pos - 1));
67: }
68:
69: /*
70:
71: PUBLIC HTAnchor * HTHistory_delete ARGS1 (HTAnchor *,cur_anch)
72: {
73: int pos = HTList_indexOf(history, cur_anch);
74: if (pos <= 0)
75: return NULL;
76: else
77: return ((HTAnchor *) HTList_objectAt(history, pos - 1));
78: }
79:
80: */
81:
82:
83: /* Browse through references in the same parent node
84: ** -------------------------------------------------
85: **
86: ** Take the n-th child's link after or before the one we took to get here.
87: ** Positive offset means go towards most recently added children.
88: */
89:
90: HTAnchor * HTHistory_moveBy ARGS1 (int,offset)
91: {
92: HTAnchor * last = (HTAnchor *) HTList_objectAt (history, 1);
93: if (! last)
94: return NULL; /* No last visited node */
95: if (last != (HTAnchor *) last->parent) { /* Was a child */
96: HTList * kids = last->parent->children;
97: int i = HTList_indexOf (kids, last);
98: HTAnchor * nextOne = (HTAnchor *) HTList_objectAt (kids, i - offset);
99: if (nextOne) {
100: HTAnchor * destination = HTAnchor_followMainLink (nextOne);
101: if (destination) {
102: HTList_removeLastObject (history);
103: HTList_removeLastObject (history);
104: HTList_addObject (history, nextOne);
105: HTList_addObject (history, destination);
106: }
107: return destination;
108: } else {
109: if (TRACE) fprintf(TDEST,
110: "HTHistory_moveBy: offset by %+d goes out of list %p.\n",
111: offset, (void*)kids);
112: return NULL;
113: }
114: } else { /* Was a parent */
115: return NULL; /* FIXME we could possibly follow the next link... */
116: }
117: }
118:
119: BOOL HTHistory_canMoveBy
120: ARGS1 (int,offset)
121: {
122: HTAnchor * last = (HTAnchor *) HTList_objectAt (history, 1);
123: if (! last)
124: return NO; /* No last visited node */
125: if (last != (HTAnchor *) last->parent) { /* Was a child */
126: HTList * kids = last->parent->children;
127: int i = HTList_indexOf (kids, last);
128: return (HTList_objectAt (kids, i - offset) != NULL);
129: } else { /* Was a parent */
130: return NO; /* FIXME we could possibly follow the next link... */
131: }
132: }
133:
134:
135: /* Retrieval
136: ** =========
137: */
138:
139: /* Read numbered visited anchor (1 is the oldest)
140: ** ----------------------------
141: */
142:
143: HTAnchor * HTHistory_read ARGS1 (int, number)
144: {
145: return (HTAnchor *) (HTList_objectAt(history,
146: HTList_count(history)-number));
147: }
148:
149:
150: /* Recall numbered visited anchor (1 is the oldest)
151: ** ------------------------------
152: ** This reads the anchor and stores it again in the list, except if last.
153: */
154:
155: HTAnchor * HTHistory_recall ARGS1 (int,number)
156: {
157: HTAnchor * destination = (HTAnchor *)
158: HTList_objectAt (history, HTList_count (history) - number);
159: if (destination && destination != HTList_lastObject (history))
160: HTList_addObject (history, destination);
161: return destination;
162: }
163:
164: /* Number of Anchors stored
165: ** ------------------------
166: **
167: ** This is needed in order to check the validity of certain commands
168: ** for menus, etc.
169: (not needed for now. Use canBacktrack, etc.)
170: int HTHistory_count
171: NOARGS
172: {
173: return HTList_count (history);
174: }
175: */
176:
177: /* Change last history entry
178: ** -------------------------
179: **
180: ** Sometimes we load a node by one anchor but leave by a different
181: ** one, and it is the one we left from which we want to remember.
182: */
183:
184: void HTHistory_leavingFrom
185: ARGS1 (HTAnchor *,anchor)
186: {
187: if (HTList_removeLastObject (history))
188: HTList_addObject (history, anchor);
189: else
190: if (TRACE) fprintf(TDEST, "HTHistory_leavingFrom: empty history !\n");
191: }
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