1/*
2 * Copyright (C) 1984-2021  Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11/*
12 * An IFILE represents an input file.
13 *
14 * It is actually a pointer to an ifile structure,
15 * but is opaque outside this module.
16 * Ifile structures are kept in a linked list in the order they
17 * appear on the command line.
18 * Any new file which does not already appear in the list is
19 * inserted after the current file.
20 */
21
22#include "less.h"
23
24extern IFILE    curr_ifile;
25
26struct ifile {
27	struct ifile *h_next;           /* Links for command line list */
28	struct ifile *h_prev;
29	char *h_filename;               /* Name of the file */
30	char *h_rfilename;              /* Canonical name of the file */
31	void *h_filestate;              /* File state (used in ch.c) */
32	int h_index;                    /* Index within command line list */
33	int h_hold;                     /* Hold count */
34	char h_opened;                  /* Has this ifile been opened? */
35	struct scrpos h_scrpos;         /* Saved position within the file */
36	void *h_altpipe;                /* Alt pipe */
37	char *h_altfilename;            /* Alt filename */
38};
39
40/*
41 * Convert an IFILE (external representation)
42 * to a struct file (internal representation), and vice versa.
43 */
44#define int_ifile(h)    ((struct ifile *)(h))
45#define ext_ifile(h)    ((IFILE)(h))
46
47/*
48 * Anchor for linked list.
49 */
50static struct ifile anchor = { &anchor, &anchor, NULL, NULL, NULL, 0, 0, '\0',
51				{ NULL_POSITION, 0 } };
52static int ifiles = 0;
53
54	static void
55incr_index(p, incr)
56	struct ifile *p;
57	int incr;
58{
59	for (;  p != &anchor;  p = p->h_next)
60		p->h_index += incr;
61}
62
63/*
64 * Link an ifile into the ifile list.
65 */
66	static void
67link_ifile(p, prev)
68	struct ifile *p;
69	struct ifile *prev;
70{
71	/*
72	 * Link into list.
73	 */
74	if (prev == NULL)
75		prev = &anchor;
76	p->h_next = prev->h_next;
77	p->h_prev = prev;
78	prev->h_next->h_prev = p;
79	prev->h_next = p;
80	/*
81	 * Calculate index for the new one,
82	 * and adjust the indexes for subsequent ifiles in the list.
83	 */
84	p->h_index = prev->h_index + 1;
85	incr_index(p->h_next, 1);
86	ifiles++;
87}
88
89/*
90 * Unlink an ifile from the ifile list.
91 */
92	static void
93unlink_ifile(p)
94	struct ifile *p;
95{
96	p->h_next->h_prev = p->h_prev;
97	p->h_prev->h_next = p->h_next;
98	incr_index(p->h_next, -1);
99	ifiles--;
100}
101
102/*
103 * Allocate a new ifile structure and stick a filename in it.
104 * It should go after "prev" in the list
105 * (or at the beginning of the list if "prev" is NULL).
106 * Return a pointer to the new ifile structure.
107 */
108	static struct ifile *
109new_ifile(filename, prev)
110	char *filename;
111	struct ifile *prev;
112{
113	struct ifile *p;
114
115	/*
116	 * Allocate and initialize structure.
117	 */
118	p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
119	p->h_filename = save(filename);
120	p->h_rfilename = lrealpath(filename);
121	p->h_scrpos.pos = NULL_POSITION;
122	p->h_opened = 0;
123	p->h_hold = 0;
124	p->h_filestate = NULL;
125	p->h_altfilename = NULL;
126	p->h_altpipe = NULL;
127	link_ifile(p, prev);
128	/*
129	 * {{ It's dodgy to call mark.c functions from here;
130	 *    there is potentially dangerous recursion.
131	 *    Probably need to revisit this design. }}
132	 */
133	mark_check_ifile(ext_ifile(p));
134	return (p);
135}
136
137/*
138 * Delete an existing ifile structure.
139 */
140	public void
141del_ifile(h)
142	IFILE h;
143{
144	struct ifile *p;
145
146	if (h == NULL_IFILE)
147		return;
148	/*
149	 * If the ifile we're deleting is the currently open ifile,
150	 * move off it.
151	 */
152	unmark(h);
153	if (h == curr_ifile)
154		curr_ifile = getoff_ifile(curr_ifile);
155	p = int_ifile(h);
156	unlink_ifile(p);
157	free(p->h_rfilename);
158	free(p->h_filename);
159	free(p);
160}
161
162/*
163 * Get the ifile after a given one in the list.
164 */
165	public IFILE
166next_ifile(h)
167	IFILE h;
168{
169	struct ifile *p;
170
171	p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
172	if (p->h_next == &anchor)
173		return (NULL_IFILE);
174	return (ext_ifile(p->h_next));
175}
176
177/*
178 * Get the ifile before a given one in the list.
179 */
180	public IFILE
181prev_ifile(h)
182	IFILE h;
183{
184	struct ifile *p;
185
186	p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
187	if (p->h_prev == &anchor)
188		return (NULL_IFILE);
189	return (ext_ifile(p->h_prev));
190}
191
192/*
193 * Return a different ifile from the given one.
194 */
195	public IFILE
196getoff_ifile(ifile)
197	IFILE ifile;
198{
199	IFILE newifile;
200
201	if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
202		return (newifile);
203	if ((newifile = next_ifile(ifile)) != NULL_IFILE)
204		return (newifile);
205	return (NULL_IFILE);
206}
207
208/*
209 * Return the number of ifiles.
210 */
211	public int
212nifile(VOID_PARAM)
213{
214	return (ifiles);
215}
216
217/*
218 * Find an ifile structure, given a filename.
219 */
220	static struct ifile *
221find_ifile(filename)
222	char *filename;
223{
224	struct ifile *p;
225	char *rfilename = lrealpath(filename);
226
227	for (p = anchor.h_next;  p != &anchor;  p = p->h_next)
228	{
229		if (strcmp(rfilename, p->h_rfilename) == 0)
230		{
231			/*
232			 * If given name is shorter than the name we were
233			 * previously using for this file, adopt shorter name.
234			 */
235			if (strlen(filename) < strlen(p->h_filename))
236			{
237				free(p->h_filename);
238				p->h_filename = save(filename);
239			}
240			break;
241		}
242	}
243	free(rfilename);
244	if (p == &anchor)
245		p = NULL;
246	return (p);
247}
248
249/*
250 * Get the ifile associated with a filename.
251 * If the filename has not been seen before,
252 * insert the new ifile after "prev" in the list.
253 */
254	public IFILE
255get_ifile(filename, prev)
256	char *filename;
257	IFILE prev;
258{
259	struct ifile *p;
260
261	if ((p = find_ifile(filename)) == NULL)
262		p = new_ifile(filename, int_ifile(prev));
263	return (ext_ifile(p));
264}
265
266/*
267 * Get the display filename associated with a ifile.
268 */
269	public char *
270get_filename(ifile)
271	IFILE ifile;
272{
273	if (ifile == NULL)
274		return (NULL);
275	return (int_ifile(ifile)->h_filename);
276}
277
278/*
279 * Get the canonical filename associated with a ifile.
280 */
281	public char *
282get_real_filename(ifile)
283	IFILE ifile;
284{
285	if (ifile == NULL)
286		return (NULL);
287	return (int_ifile(ifile)->h_rfilename);
288}
289
290/*
291 * Get the index of the file associated with a ifile.
292 */
293	public int
294get_index(ifile)
295	IFILE ifile;
296{
297	return (int_ifile(ifile)->h_index);
298}
299
300/*
301 * Save the file position to be associated with a given file.
302 */
303	public void
304store_pos(ifile, scrpos)
305	IFILE ifile;
306	struct scrpos *scrpos;
307{
308	int_ifile(ifile)->h_scrpos = *scrpos;
309}
310
311/*
312 * Recall the file position associated with a file.
313 * If no position has been associated with the file, return NULL_POSITION.
314 */
315	public void
316get_pos(ifile, scrpos)
317	IFILE ifile;
318	struct scrpos *scrpos;
319{
320	*scrpos = int_ifile(ifile)->h_scrpos;
321}
322
323/*
324 * Mark the ifile as "opened".
325 */
326	public void
327set_open(ifile)
328	IFILE ifile;
329{
330	int_ifile(ifile)->h_opened = 1;
331}
332
333/*
334 * Return whether the ifile has been opened previously.
335 */
336	public int
337opened(ifile)
338	IFILE ifile;
339{
340	return (int_ifile(ifile)->h_opened);
341}
342
343	public void
344hold_ifile(ifile, incr)
345	IFILE ifile;
346	int incr;
347{
348	int_ifile(ifile)->h_hold += incr;
349}
350
351	public int
352held_ifile(ifile)
353	IFILE ifile;
354{
355	return (int_ifile(ifile)->h_hold);
356}
357
358	public void *
359get_filestate(ifile)
360	IFILE ifile;
361{
362	return (int_ifile(ifile)->h_filestate);
363}
364
365	public void
366set_filestate(ifile, filestate)
367	IFILE ifile;
368	void *filestate;
369{
370	int_ifile(ifile)->h_filestate = filestate;
371}
372
373	public void
374set_altpipe(ifile, p)
375	IFILE ifile;
376	void *p;
377{
378	int_ifile(ifile)->h_altpipe = p;
379}
380
381	public void *
382get_altpipe(ifile)
383	IFILE ifile;
384{
385	return (int_ifile(ifile)->h_altpipe);
386}
387
388	public void
389set_altfilename(ifile, altfilename)
390	IFILE ifile;
391	char *altfilename;
392{
393	struct ifile *p = int_ifile(ifile);
394	if (p->h_altfilename != NULL && p->h_altfilename != altfilename)
395		free(p->h_altfilename);
396	p->h_altfilename = altfilename;
397}
398
399	public char *
400get_altfilename(ifile)
401	IFILE ifile;
402{
403	return (int_ifile(ifile)->h_altfilename);
404}
405
406#if 0
407	public void
408if_dump(VOID_PARAM)
409{
410	struct ifile *p;
411
412	for (p = anchor.h_next;  p != &anchor;  p = p->h_next)
413	{
414		printf("%x: %d. <%s> pos %d,%x\n",
415			p, p->h_index, p->h_filename,
416			p->h_scrpos.ln, p->h_scrpos.pos);
417		ch_dump(p->h_filestate);
418	}
419}
420#endif
421