1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <cursor.h>
5 #include <event.h>
6 #include <bio.h>
7 #include <plumb.h>
8 #include <ctype.h>
9 #include <keyboard.h>
10 #include <thread.h>
11 #include "page.h"
12 
13 typedef struct Cached Cached;
14 struct Cached
15 {
16 	Document *doc;
17 	int page;
18 	int angle;
19 	Image *im;
20 	int ppi;
21 };
22 
23 static Cached cache[5];
24 static int rabusy;
25 
26 static Image*
27 questionmark(void)
28 {
29 	static Image *im;
30 
31 	if(im)
32 		return im;
33 	im = xallocimage(display, Rect(0,0,50,50), GREY1, 1, DBlack);
34 	if(im == nil)
35 		return nil;
36 	string(im, ZP, display->white, ZP, display->defaultfont, "?");
37 	return im;
38 }
39 
40 void
41 cacheflush(void)
42 {
43 	int i;
44 	Cached *c;
45 
46 	for(i=0; i<nelem(cache); i++){
47 		c = &cache[i];
48 		if(c->im)
49 			freeimage(c->im);
50 		c->im = nil;
51 		c->doc = nil;
52 	}
53 }
54 
55 static Image*
56 _cachedpage(Document *doc, int angle, int page, char *ra)
57 {
58 	int i;
59 	Cached *c, old;
60 	Image *im, *tmp;
61 	int ppi = 100;
62 	PDFInfo *pdf;
63 	PSInfo *ps;
64 
65 	if((page < 0 || page >= doc->npage) && !doc->fwdonly)
66 		return nil;
67 
68 	if (doc->type == Tpdf){
69 		pdf = (PDFInfo *) doc->extra;
70 		ppi = pdf->gs.ppi;
71 	}
72 	else{
73 		if (doc->type == Tps){
74 			ps = (PSInfo *) doc->extra;
75 			ppi = ps->gs.ppi;
76 		}
77 	}
78 
79 Again:
80 	for(i=0; i<nelem(cache); i++){
81 		c = &cache[i];
82 		if(c->doc == doc && c->angle == angle && c->page == page && c->ppi == ppi){
83 			if(chatty) fprint(2, "cache%s hit %d\n", ra, page);
84 			goto Found;
85 		}
86 		if(c->doc == nil)
87 			break;
88 	}
89 
90 	if(i >= nelem(cache))
91 		i = nelem(cache)-1;
92 	c = &cache[i];
93 	if(c->im)
94 		freeimage(c->im);
95 	c->im = nil;
96 	c->doc = nil;
97 	c->page = -1;
98 	c->ppi = -1;
99 
100 	if(chatty) fprint(2, "cache%s load %d\n", ra, page);
101 	im = doc->drawpage(doc, page);
102 	if(im == nil){
103 		if(doc->fwdonly)	/* end of file */
104 			wexits(0);
105 		im = questionmark();
106 		if(im == nil){
107 		Flush:
108 			if(i > 0){
109 				cacheflush();
110 				goto Again;
111 			}
112 			fprint(2, "out of memory: %r\n");
113 			wexits("memory");
114 		}
115 		return im;
116 	}
117 
118 	if(im->r.min.x != 0 || im->r.min.y != 0){
119 		/* translate to 0,0 */
120 		tmp = xallocimage(display, Rect(0, 0, Dx(im->r), Dy(im->r)), im->chan, 0, DNofill);
121 		if(tmp == nil){
122 			freeimage(im);
123 			goto Flush;
124 		}
125 		drawop(tmp, tmp->r, im, nil, im->r.min, S);
126 		freeimage(im);
127 		im = tmp;
128 	}
129 
130 	switch(angle){
131 	case 90:
132 		im = rot90(im);
133 		break;
134 	case 180:
135 		rot180(im);
136 		break;
137 	case 270:
138 		im = rot270(im);
139 		break;
140 	}
141 	if(im == nil)
142 		goto Flush;
143 
144 	c->doc = doc;
145 	c->page = page;
146 	c->angle = angle;
147 	c->im = im;
148 	c->ppi = ppi;
149 
150 Found:
151 	if(chatty) fprint(2, "cache%s mtf %d @%d:", ra, c->page, i);
152 	old = *c;
153 	memmove(cache+1, cache, (c-cache)*sizeof cache[0]);
154 	cache[0] = old;
155 	if(chatty){
156 		for(i=0; i<nelem(cache); i++)
157 			fprint(2, " %d", cache[i].page);
158 		fprint(2, "\n");
159 	}
160 	if(chatty) fprint(2, "cache%s return %d %p\n", ra, old.page, old.im);
161 	return old.im;
162 }
163 
164 static void
165 raproc(void *a)
166 {
167 	Cached *c;
168 
169 	c = a;
170 	lockdisplay(display);
171 	/*
172 	 * If there is only one page in a fwdonly file, we may reach EOF
173 	 * while doing readahead and page will exit without showing anything.
174 	 */
175 	if(!c->doc->fwdonly)
176 		_cachedpage(c->doc, c->angle, c->page, "-ra");
177 	rabusy = 0;
178 	unlockdisplay(display);
179 	free(c);
180 	threadexits(0);
181 }
182 
183 Image*
184 cachedpage(Document *doc, int angle, int page)
185 {
186 	static int lastpage = -1;
187 	Cached *c;
188 	Image *im;
189 	int ra;
190 
191 	if(doc->npage < 1)
192 		return display->white;
193 
194 	im = _cachedpage(doc, angle, page, "");
195 	if(im == nil)
196 		return nil;
197 
198 	/* readahead */
199 	ra = -1;
200 	if(!rabusy){
201 		if(page == lastpage+1)
202 			ra = page+1;
203 		else if(page == lastpage-1)
204 			ra = page-1;
205 	}
206 	lastpage = page;
207 	if(ra >= 0){
208 		c = emalloc(sizeof(*c));
209 		c->doc = doc;
210 		c->angle = angle;
211 		c->page = ra;
212 		c->im = nil;
213 		rabusy = 1;
214 		if(proccreate(raproc, c, mainstacksize) == -1)
215 			rabusy = 0;
216 	}
217 	return im;
218 }