page: move cmd/page/cache.c to src/cmd/page/cache.c

not sure how the codebot screwed that up.

src/cmd/page/cache.c

@@ -0,0 +1,196 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <cursor.h>
+#include <event.h>
+#include <bio.h>
+#include <plumb.h>
+#include <ctype.h>
+#include <keyboard.h>
+#include <thread.h>
+#include "page.h"
+
+typedef struct Cached Cached;
+struct Cached
+{
+	Document *doc;
+	int page;
+	int angle;
+	Image *im;
+};
+
+static Cached cache[5];
+static int rabusy;
+
+static Image*
+questionmark(void)
+{
+	static Image *im;
+
+	if(im)
+		return im;	
+	im = xallocimage(display, Rect(0,0,50,50), GREY1, 1, DBlack);
+	if(im == nil)
+		return nil;
+	string(im, ZP, display->white, ZP, display->defaultfont, "?");
+	return im;
+}
+
+void
+cacheflush(void)
+{
+	int i;
+	Cached *c;
+
+	for(i=0; i<nelem(cache); i++){
+		c = &cache[i];
+		if(c->im)
+			freeimage(c->im);
+		c->im = nil;
+		c->doc = nil;
+	}
+}
+
+static Image*
+_cachedpage(Document *doc, int angle, int page, char *ra)
+{
+	int i;
+	Cached *c, old;
+	Image *im, *tmp;
+
+	if((page < 0 || page >= doc->npage) && !doc->fwdonly)
+		return nil;
+
+Again:
+	for(i=0; i<nelem(cache); i++){
+		c = &cache[i];
+		if(c->doc == doc && c->angle == angle && c->page == page){
+			if(chatty) fprint(2, "cache%s hit %d\n", ra, page);
+			goto Found;
+		}
+		if(c->doc == nil)
+			break;
+	}
+
+	if(i >= nelem(cache))
+		i = nelem(cache)-1;
+	c = &cache[i];
+	if(c->im)
+		freeimage(c->im);
+	c->im = nil;
+	c->doc = nil;
+	c->page = -1;
+
+	if(chatty) fprint(2, "cache%s load %d\n", ra, page);
+	im = doc->drawpage(doc, page);
+	if(im == nil){
+		if(doc->fwdonly)	/* end of file */
+			wexits(0);
+		im = questionmark();
+		if(im == nil){
+		Flush:
+			if(i > 0){
+				cacheflush();
+				goto Again;
+			}
+			fprint(2, "out of memory: %r\n");
+			wexits("memory");
+		}
+		return im;
+	}
+
+	if(im->r.min.x != 0 || im->r.min.y != 0){
+		/* translate to 0,0 */
+		tmp = xallocimage(display, Rect(0, 0, Dx(im->r), Dy(im->r)), im->chan, 0, DNofill);
+		if(tmp == nil){
+			freeimage(im);
+			goto Flush;
+		}
+		drawop(tmp, tmp->r, im, nil, im->r.min, S);
+		freeimage(im);
+		im = tmp;
+	}
+
+	switch(angle){
+	case 90:
+		im = rot90(im);
+		break;
+	case 180:
+		rot180(im);
+		break;
+	case 270:
+		im = rot270(im);
+		break;
+	}
+	if(im == nil)
+		goto Flush;
+
+	c->doc = doc;
+	c->page = page;
+	c->angle = angle;
+	c->im = im;
+
+Found:
+	if(chatty) fprint(2, "cache%s mtf %d @%d:", ra, c->page, i);
+	old = *c;
+	memmove(cache+1, cache, (c-cache)*sizeof cache[0]);
+	cache[0] = old;
+	if(chatty){
+		for(i=0; i<nelem(cache); i++)
+			fprint(2, " %d", cache[i].page);
+		fprint(2, "\n");
+	}
+	if(chatty) fprint(2, "cache%s return %d %p\n", ra, old.page, old.im);
+	return old.im;
+}
+
+static void
+raproc(void *a)
+{
+	Cached *c;
+	
+	c = a;
+	lockdisplay(display);
+	_cachedpage(c->doc, c->angle, c->page, "-ra");
+	rabusy = 0;
+	unlockdisplay(display);
+	free(c);
+	threadexits(0);
+}
+
+Image*
+cachedpage(Document *doc, int angle, int page)
+{
+	static int lastpage = -1;
+	Cached *c;
+	Image *im;
+	int ra;
+	
+	if(doc->npage < 1)
+		return display->white;
+
+	im = _cachedpage(doc, angle, page, "");
+	if(im == nil)
+		return nil;
+
+	/* readahead */
+	ra = -1;
+	if(!rabusy){
+		if(page == lastpage+1)
+			ra = page+1;
+		else if(page == lastpage-1)
+			ra = page-1;
+	}
+	lastpage = page;
+	if(ra >= 0){
+		c = emalloc(sizeof(*c));
+		c->doc = doc;
+		c->angle = angle;
+		c->page = ra;
+		c->im = nil;
+		rabusy = 1;
+		if(proccreate(raproc, c, mainstacksize) == -1)
+			rabusy = 0;
+	}
+	return im;
+}