Move to exception handling rather than error passing throughout.

This frees us from passing errors back everywhere, and hence enables us
to pass results back as return values.

Rather than having to explicitly check for errors everywhere and bubble
them, we now allow exception handling to do the work for us; the
downside to this is that we no longer emit as much debugging information
as we did before (though this could be put back in). For now, the
debugging information we have lost has been retained in comments
with 'RJW:' at the start.

This code needs fuller testing, but is being committed as a work in
progress.

7 files changed, 240 insertions, 131 deletions

diff --git a/apps/pdfapp.c b/apps/pdfapp.c
index c992b504..5e235ddf 100644
--- a/apps/pdfapp.c
+++ b/apps/pdfapp.c
@@ -100,20 +100,25 @@ void pdfapp_invert(pdfapp_t *app, fz_bbox rect)
 
 static void pdfapp_open_pdf(pdfapp_t *app, char *filename, int fd)
 {
-	fz_error error;
 	fz_stream *file;
 	char *password = "";
 	fz_obj *obj;
 	fz_obj *info;
+	fz_context *ctx = app->ctx;
 
 	/*
 	 * Open PDF and load xref table
 	 */
 
-	file = fz_open_fd(app->ctx, fd);
-	error = pdf_open_xref_with_stream(&app->xref, file, NULL);
-	if (error)
-		pdfapp_error(app, fz_error_note(error, "cannot open document '%s'", filename));
+	file = fz_open_fd(ctx, fd);
+	fz_try(ctx)
+	{
+		app->xref = pdf_open_xref_with_stream(file, NULL);
+	}
+	fz_catch(ctx)
+	{
+		pdfapp_error(app, fz_error_note(1, "cannot open document '%s'", filename));
+	}
 	fz_close(file);
 
 	/*
@@ -150,29 +155,38 @@ static void pdfapp_open_pdf(pdfapp_t *app, char *filename, int fd)
 	{
 		obj = fz_dict_gets(info, "Title");
 		if (obj)
-			app->doctitle = pdf_to_utf8(app->ctx, obj);
+			app->doctitle = pdf_to_utf8(ctx, obj);
 	}
 
 	/*
 	 * Start at first page
 	 */
 
-	error = pdf_load_page_tree(app->xref);
-	if (error)
-		pdfapp_error(app, fz_error_note(error, "cannot load page tree"));
+	fz_try(ctx)
+	{
+		pdf_load_page_tree(app->xref);
+	}
+	fz_catch(ctx)
+	{
+		pdfapp_error(app, fz_error_note(1, "cannot load page tree"));
+	}
 
 	app->pagecount = pdf_count_pages(app->xref);
 }
 
 static void pdfapp_open_xps(pdfapp_t *app, char *filename, int fd)
 {
-	fz_error error;
 	fz_stream *file;
 
 	file = fz_open_fd(app->ctx, fd);
-	error = xps_open_stream(&app->xps, file);
-	if (error)
-		pdfapp_error(app, fz_error_note(error, "cannot open document '%s'", filename));
+	fz_try(app->ctx)
+	{
+		app->xps = xps_open_stream(file);
+	}
+	fz_catch(app->ctx)
+	{
+		pdfapp_error(app, fz_error_note(-1, "cannot open document '%s'", filename));
+	}
 	fz_close(file);
 
 	app->doctitle = filename;
@@ -282,12 +296,16 @@ static void pdfapp_panview(pdfapp_t *app, int newx, int newy)
 static void pdfapp_loadpage_pdf(pdfapp_t *app)
 {
 	pdf_page *page;
-	fz_error error;
 	fz_device *mdev;
 
-	error = pdf_load_page(&page, app->xref, app->pageno - 1);
-	if (error)
-		pdfapp_error(app, error);
+	fz_try(app->ctx)
+	{
+		page = pdf_load_page(app->xref, app->pageno - 1);
+	}
+	fz_catch(app->ctx)
+	{
+		pdfapp_error(app, 1);
+	}
 
 	app->page_bbox = page->mediabox;
 	app->page_rotate = page->rotate;
@@ -297,11 +315,13 @@ static void pdfapp_loadpage_pdf(pdfapp_t *app)
 	/* Create display list */
 	app->page_list = fz_new_display_list(app->ctx);
 	mdev = fz_new_list_device(app->ctx, app->page_list);
-	error = pdf_run_page(app->xref, page, mdev, fz_identity);
-	if (error)
+	fz_try(app->ctx)
 	{
-		error = fz_error_note(error, "cannot draw page %d in '%s'", app->pageno, app->doctitle);
-		pdfapp_error(app, error);
+		pdf_run_page(app->xref, page, mdev, fz_identity);
+	}
+	fz_catch(app->ctx)
+	{
+		pdfapp_error(app, fz_error_note(-1, "cannot draw page %d in '%s'", app->pageno, app->doctitle));
 	}
 	fz_free_device(mdev);
 
@@ -314,11 +334,15 @@ static void pdfapp_loadpage_xps(pdfapp_t *app)
 {
 	xps_page *page;
 	fz_device *mdev;
-	fz_error error;
 
-	error = xps_load_page(&page, app->xps, app->pageno - 1);
-	if (error)
-		pdfapp_error(app, fz_error_note(error, "cannot load page %d in file '%s'", app->pageno, app->doctitle));
+	fz_try(app->ctx)
+	{
+		page = xps_load_page(app->xps, app->pageno - 1);
+	}
+	fz_catch(app->ctx)
+	{
+		pdfapp_error(app, fz_error_note(1, "cannot load page %d in file '%s'", app->pageno, app->doctitle));
+	}
 
 	app->page_bbox.x0 = 0;
 	app->page_bbox.y0 = 0;
diff --git a/apps/pdfclean.c b/apps/pdfclean.c
index 4b5fa139..4b76afa2 100644
--- a/apps/pdfclean.c
+++ b/apps/pdfclean.c
@@ -287,13 +287,17 @@ static void renumberobjs(void)
 
 static void retainpages(int argc, char **argv)
 {
-	fz_error error;
 	fz_obj *oldroot, *root, *pages, *kids, *countobj, *parent;
 
 	/* Load the old page tree */
-	error = pdf_load_page_tree(xref);
-	if (error)
-		die(fz_error_note(error, "cannot load page tree"));
+	fz_try(xref->ctx)
+	{
+		pdf_load_page_tree(xref);
+	}
+	fz_catch(xref->ctx)
+	{
+		die(fz_error_note(1, "cannot load page tree"));
+	}
 
 	/* Keep only pages/type entry to avoid references to unretained pages */
 	oldroot = fz_dict_gets(xref->trailer, "Root");
@@ -377,7 +381,6 @@ static void retainpages(int argc, char **argv)
 
 static void preloadobjstms(void)
 {
-	fz_error error;
 	fz_obj *obj;
 	int num;
 
@@ -385,9 +388,14 @@ static void preloadobjstms(void)
 	{
 		if (xref->table[num].type == 'o')
 		{
-			error = pdf_load_object(&obj, xref, num, 0);
-			if (error)
-				die(error);
+			fz_try(ctx)
+			{
+				obj = pdf_load_object(xref, num, 0);
+			}
+			fz_catch(ctx)
+			{
+				die(1);
+			}
 			fz_drop_obj(obj);
 		}
 	}
@@ -488,13 +496,17 @@ static void addhexfilter(fz_obj *dict)
 
 static void copystream(fz_obj *obj, int num, int gen)
 {
-	fz_error error;
 	fz_buffer *buf, *tmp;
 	fz_obj *newlen;
 
-	error = pdf_load_raw_stream(&buf, xref, num, gen);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		buf = pdf_load_raw_stream(xref, num, gen);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	if (doascii && isbinarystream(buf))
 	{
@@ -520,13 +532,17 @@ static void copystream(fz_obj *obj, int num, int gen)
 
 static void expandstream(fz_obj *obj, int num, int gen)
 {
-	fz_error error;
 	fz_buffer *buf, *tmp;
 	fz_obj *newlen;
 
-	error = pdf_load_stream(&buf, xref, num, gen);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		buf = pdf_load_stream(xref, num, gen);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	fz_dict_dels(obj, "Filter");
 	fz_dict_dels(obj, "DecodeParms");
@@ -555,13 +571,17 @@ static void expandstream(fz_obj *obj, int num, int gen)
 
 static void writeobject(int num, int gen)
 {
-	fz_error error;
 	fz_obj *obj;
 	fz_obj *type;
 
-	error = pdf_load_object(&obj, xref, num, gen);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		obj = pdf_load_object(xref, num, gen);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	/* skip ObjStm and XRef objects */
 	if (fz_is_dict(obj))
@@ -686,7 +706,6 @@ static void writepdf(void)
 
 int main(int argc, char **argv)
 {
-	fz_error error;
 	char *infile;
 	char *outfile = "out.pdf";
 	char *password = "";
@@ -724,9 +743,14 @@ int main(int argc, char **argv)
 	if (ctx == NULL)
 		die(fz_error_note(1, "failed to initialise context"));
 
-	error = pdf_open_xref(ctx, &xref, infile, password);
-	if (error)
-		die(fz_error_note(error, "cannot open input file '%s'", infile));
+	fz_try(ctx)
+	{
+		xref = pdf_open_xref(ctx, infile, password);
+	}
+	fz_catch(ctx)
+	{
+		die(fz_error_note(1, "cannot open input file '%s'", infile));
+	}
 
 	out = fopen(outfile, "wb");
 	if (!out)
diff --git a/apps/pdfdraw.c b/apps/pdfdraw.c
index c65ef059..af21b9ea 100644
--- a/apps/pdfdraw.c
+++ b/apps/pdfdraw.c
@@ -92,7 +92,6 @@ static int isrange(char *s)
 
 static void drawpage(pdf_xref *xref, int pagenum)
 {
-	fz_error error;
 	pdf_page *page;
 	fz_display_list *list;
 	fz_device *dev;
@@ -104,9 +103,14 @@ static void drawpage(pdf_xref *xref, int pagenum)
 		start = gettime();
 	}
 
-	error = pdf_load_page(&page, xref, pagenum - 1);
-	if (error)
-		die(fz_error_note(error, "cannot load page %d in file '%s'", pagenum, filename));
+	fz_try(ctx)
+	{
+		page = pdf_load_page(xref, pagenum - 1);
+	}
+	fz_catch(ctx)
+	{
+		die(fz_error_note(1, "cannot load page %d in file '%s'", pagenum, filename));
+	}
 
 	list = NULL;
 
@@ -114,9 +118,14 @@ static void drawpage(pdf_xref *xref, int pagenum)
 	{
 		list = fz_new_display_list(ctx);
 		dev = fz_new_list_device(ctx, list);
-		error = pdf_run_page(xref, page, dev, fz_identity);
-		if (error)
-			die(fz_error_note(error, "cannot draw page %d in file '%s'", pagenum, filename));
+		fz_try(ctx)
+		{
+			pdf_run_page(xref, page, dev, fz_identity);
+		}
+		fz_catch(ctx)
+		{
+			die(fz_error_note(1, "cannot draw page %d in file '%s'", pagenum, filename));
+		}
 		fz_free_device(dev);
 	}
 
@@ -193,15 +202,15 @@ static void drawpage(pdf_xref *xref, int pagenum)
 			char buf[512];
 			sprintf(buf, output, pagenum);
 			if (strstr(output, ".pgm") || strstr(output, ".ppm") || strstr(output, ".pnm"))
-				fz_write_pnm(pix, buf);
+				fz_write_pnm(ctx, pix, buf);
 			else if (strstr(output, ".pam"))
-				fz_write_pam(pix, buf, savealpha);
+				fz_write_pam(ctx, pix, buf, savealpha);
 			else if (strstr(output, ".png"))
 				fz_write_png(ctx, pix, buf, savealpha);
 			else if (strstr(output, ".pbm")) {
 				fz_halftone *ht = fz_get_default_halftone(ctx, 1);
 				fz_bitmap *bit = fz_halftone_pixmap(ctx, pix, ht);
-				fz_write_pbm(bit, buf);
+				fz_write_pbm(ctx, bit, buf);
 				fz_drop_bitmap(ctx, bit);
 				fz_drop_halftone(ctx, ht);
 			}
@@ -376,13 +385,23 @@ int main(int argc, char **argv)
 	{
 		filename = argv[fz_optind++];
 
-		error = pdf_open_xref(ctx, &xref, filename, password);
-		if (error)
+		fz_try(ctx)
+		{
+			xref = pdf_open_xref(ctx, filename, password);
+		}
+		fz_catch(ctx)
+		{
 			die(fz_error_note(error, "cannot open document: %s", filename));
+		}
 
-		error = pdf_load_page_tree(xref);
-		if (error)
+		fz_try(ctx)
+		{
+			pdf_load_page_tree(xref);
+		}
+		fz_catch(ctx)
+		{
 			die(fz_error_note(error, "cannot load page tree: %s", filename));
+		}
 
 		if (showxml)
 			printf("<document name=\"%s\">\n", filename);
diff --git a/apps/pdfextract.c b/apps/pdfextract.c
index 7e09226e..5aa5fa09 100644
--- a/apps/pdfextract.c
+++ b/apps/pdfextract.c
@@ -39,7 +39,6 @@ static int isfontdesc(fz_obj *obj)
 
 static void saveimage(int num)
 {
-	fz_error error;
 	fz_pixmap *img;
 	fz_obj *ref;
 	char name[1024];
@@ -48,9 +47,14 @@ static void saveimage(int num)
 
 	/* TODO: detect DCTD and save as jpeg */
 
-	error = pdf_load_image(&img, xref, ref);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		img = pdf_load_image(xref, ref);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	if (dorgb && img->colorspace && img->colorspace != fz_device_rgb)
 	{
@@ -71,7 +75,7 @@ static void saveimage(int num)
 	{
 		sprintf(name, "img-%04d.pam", num);
 		printf("extracting image %s\n", name);
-		fz_write_pam(img, name, 0);
+		fz_write_pam(ctx, img, name, 0);
 	}
 
 	fz_drop_pixmap(ctx, img);
@@ -80,7 +84,6 @@ static void saveimage(int num)
 
 static void savefont(fz_obj *dict, int num)
 {
-	fz_error error;
 	char name[1024];
 	char *subtype;
 	fz_buffer *buf;
@@ -133,11 +136,14 @@ static void savefont(fz_obj *dict, int num)
 		return;
 	}
 
-	buf = fz_new_buffer(ctx, 0);
-
-	error = pdf_load_stream(&buf, xref, fz_to_num(stream), fz_to_gen(stream));
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		buf = pdf_load_stream(xref, fz_to_num(stream), fz_to_gen(stream));
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	sprintf(name, "%s-%04d.%s", fontname, num, ext);
 	printf("extracting font %s\n", name);
@@ -158,15 +164,19 @@ static void savefont(fz_obj *dict, int num)
 
 static void showobject(int num)
 {
-	fz_error error;
 	fz_obj *obj;
 
 	if (!xref)
 		die(fz_error_make("no file specified"));
 
-	error = pdf_load_object(&obj, xref, num, 0);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		obj = pdf_load_object(xref, num, 0);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	if (isimage(obj))
 		saveimage(num);
@@ -178,7 +188,6 @@ static void showobject(int num)
 
 int main(int argc, char **argv)
 {
-	fz_error error;
 	char *infile;
 	char *password = "";
 	int c, o;
@@ -202,9 +211,14 @@ int main(int argc, char **argv)
 	if (ctx == NULL)
 		die(fz_error_note(1, "failed to initialise context"));
 
-	error = pdf_open_xref(ctx, &xref, infile, password);
-	if (error)
-		die(fz_error_note(error, "cannot open input file '%s'", infile));
+	fz_try(ctx)
+	{
+		xref = pdf_open_xref(ctx, infile, password);
+	}
+	fz_catch(ctx)
+	{
+		die(fz_error_note(1, "cannot open input file '%s'", infile));
+	}
 
 	if (fz_optind == argc)
 	{
diff --git a/apps/pdfshow.c b/apps/pdfshow.c
index fb4bebd1..21c3a8e1 100644
--- a/apps/pdfshow.c
+++ b/apps/pdfshow.c
@@ -47,7 +47,6 @@ static void showxref(void)
 
 static void showpagetree(void)
 {
-	fz_error error;
 	fz_obj *ref;
 	int count;
 	int i;
@@ -57,9 +56,14 @@ static void showpagetree(void)
 
 	if (!xref->page_len)
 	{
-		error = pdf_load_page_tree(xref);
-		if (error)
-			die(fz_error_note(error, "cannot load page tree"));
+		fz_try(xref->ctx)
+		{
+			pdf_load_page_tree(xref);
+		}
+		fz_catch(xref->ctx)
+		{
+			die(fz_error_note(1, "cannot load page tree"));
+		}
 	}
 
 	count = pdf_count_pages(xref);
@@ -96,19 +100,23 @@ static void showsafe(unsigned char *buf, int n)
 
 static void showstream(int num, int gen)
 {
-	fz_error error;
 	fz_stream *stm;
 	unsigned char buf[2048];
 	int n;
 
 	showcolumn = 0;
 
-	if (showdecode)
-		error = pdf_open_stream(&stm, xref, num, gen);
-	else
-		error = pdf_open_raw_stream(&stm, xref, num, gen);
-	if (error)
-		die(error);
+	fz_try(xref->ctx)
+	{
+		if (showdecode)
+			stm = pdf_open_stream(xref, num, gen);
+		else
+			stm = pdf_open_raw_stream(xref, num, gen);
+	}
+	fz_catch(xref->ctx)
+	{
+		die(1);
+	}
 
 	while (1)
 	{
@@ -128,15 +136,19 @@ static void showstream(int num, int gen)
 
 static void showobject(int num, int gen)
 {
-	fz_error error;
 	fz_obj *obj;
 
 	if (!xref)
 		die(fz_error_make("no file specified"));
 
-	error = pdf_load_object(&obj, xref, num, gen);
-	if (error)
-		die(error);
+	fz_try(ctx)
+	{
+		obj = pdf_load_object(xref, num, gen);
+	}
+	fz_catch(ctx)
+	{
+		die(1);
+	}
 
 	if (pdf_is_stream(xref, num, gen))
 	{
@@ -166,7 +178,6 @@ static void showobject(int num, int gen)
 
 static void showgrep(char *filename)
 {
-	fz_error error;
 	fz_obj *obj;
 	int i;
 
@@ -174,9 +185,14 @@ static void showgrep(char *filename)
 	{
 		if (xref->table[i].type == 'n' || xref->table[i].type == 'o')
 		{
-			error = pdf_load_object(&obj, xref, i, 0);
-			if (error)
-				die(error);
+			fz_try(ctx)
+			{
+				obj = pdf_load_object(xref, i, 0);
+			}
+			fz_catch(ctx)
+			{
+				die(1);
+			}
 
 			fz_sort_dict(obj);
 
@@ -195,7 +211,6 @@ int main(int argc, char **argv)
 {
 	char *password = NULL; /* don't throw errors if encrypted */
 	char *filename;
-	fz_error error;
 	int c;
 
 	while ((c = fz_getopt(argc, argv, "p:be")) != -1)
@@ -218,9 +233,14 @@ int main(int argc, char **argv)
 	if (ctx == NULL)
 		die(fz_error_note(1, "failed to initialise context"));
 
-	error = pdf_open_xref(ctx, &xref, filename, password);
-	if (error)
-		die(fz_error_note(error, "cannot open document: %s", filename));
+	fz_try(ctx)
+	{
+		xref = pdf_open_xref(ctx, filename, password);
+	}
+	fz_catch(ctx)
+	{
+		die(fz_error_note(1, "cannot open document: %s", filename));
+	}
 
 	if (fz_optind == argc)
 		showtrailer();
diff --git a/apps/win_main.c b/apps/win_main.c
index 24279e1d..a77347e4 100644
--- a/apps/win_main.c
+++ b/apps/win_main.c
@@ -241,7 +241,7 @@ dloginfoproc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 			SetDlgItemTextA(hwnd, 0x13, "n/a");
 		}
 
-		info = fz_dict_gets(xref->ctx, xref->trailer, "Info");
+		info = fz_dict_gets(xref->trailer, "Info");
 		if (!info)
 			return TRUE;
 
@@ -253,21 +253,21 @@ dloginfoproc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 			fz_free(context, ucs); \
 		}
 
-		if ((obj = fz_dict_gets(xref->ctx, info, "Title")))
+		if ((obj = fz_dict_gets(info, "Title")))
 			SETUCS(0x20);
-		if ((obj = fz_dict_gets(xref->ctx, info, "Author")))
+		if ((obj = fz_dict_gets(info, "Author")))
 			SETUCS(0x21);
-		if ((obj = fz_dict_gets(xref->ctx, info, "Subject")))
+		if ((obj = fz_dict_gets(info, "Subject")))
 			SETUCS(0x22);
-		if ((obj = fz_dict_gets(xref->ctx, info, "Keywords")))
+		if ((obj = fz_dict_gets(info, "Keywords")))
 			SETUCS(0x23);
-		if ((obj = fz_dict_gets(xref->ctx, info, "Creator")))
+		if ((obj = fz_dict_gets(info, "Creator")))
 			SETUCS(0x24);
-		if ((obj = fz_dict_gets(xref->ctx, info, "Producer")))
+		if ((obj = fz_dict_gets(info, "Producer")))
 			SETUCS(0x25);
-		if ((obj = fz_dict_gets(xref->ctx, info, "CreationDate")))
+		if ((obj = fz_dict_gets(info, "CreationDate")))
 			SETUCS(0x26);
-		if ((obj = fz_dict_gets(xref->ctx, info, "ModDate")))
+		if ((obj = fz_dict_gets(info, "ModDate")))
 			SETUCS(0x27);
 		return TRUE;
 
@@ -858,7 +858,7 @@ WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShow
 
 	fz_accelerate();
 
-	ctx = fz_context_init(&fz_alloc_default);
+	ctx = fz_new_context(/*&fz_alloc_default*/);
 	if (ctx == NULL)
 	{
 		fprintf(stderr, "Failed to init context");
diff --git a/apps/xpsdraw.c b/apps/xpsdraw.c
index 4544d09c..19cf600a 100644
--- a/apps/xpsdraw.c
+++ b/apps/xpsdraw.c
@@ -20,7 +20,7 @@ int uselist = 1;
 fz_colorspace *colorspace;
 fz_glyph_cache *glyphcache;
 char *filename;
-fz_context *fzctx;
+fz_context *ctx;
 
 struct {
 	int count, total;
@@ -91,16 +91,20 @@ static void drawpage(xps_document *doc, int pagenum)
 	fz_display_list *list;
 	fz_device *dev;
 	int start;
-	int code;
 
 	if (showtime)
 	{
 		start = gettime();
 	}
 
-	code = xps_load_page(&page, doc, pagenum - 1);
-	if (code)
-		die(fz_error_note(code, "cannot load page %d in file '%s'", pagenum, filename));
+	fz_try(doc->ctx)
+	{
+		page = xps_load_page(doc, pagenum - 1);
+	}
+	fz_catch(doc->ctx)
+	{
+		die(fz_error_note(1, "cannot load page %d in file '%s'", pagenum, filename));
+	}
 
 	list = NULL;
 
@@ -183,9 +187,9 @@ static void drawpage(xps_document *doc, int pagenum)
 			char buf[512];
 			sprintf(buf, output, pagenum);
 			if (strstr(output, ".pgm") || strstr(output, ".ppm") || strstr(output, ".pnm"))
-				fz_write_pnm(pix, buf);
+				fz_write_pnm(doc->ctx, pix, buf);
 			else if (strstr(output, ".pam"))
-				fz_write_pam(pix, buf, savealpha);
+				fz_write_pam(doc->ctx, pix, buf, savealpha);
 			else if (strstr(output, ".png"))
 				fz_write_png(doc->ctx, pix, buf, savealpha);
 		}
@@ -278,7 +282,6 @@ int main(int argc, char **argv)
 	int grayscale = 0;
 	int accelerate = 1;
 	xps_document *doc;
-	int code;
 	int c;
 
 	while ((c = fz_getopt(argc, argv, "o:p:r:Aadgmtx5")) != -1)
@@ -311,14 +314,14 @@ int main(int argc, char **argv)
 	if (accelerate)
 		fz_accelerate();
 
-	fzctx = fz_new_context();
-	if (fzctx == NULL)
+	ctx = fz_new_context();
+	if (ctx == NULL)
 	{
 		fprintf(stderr, "failed to initialise context");
 		exit(1);
 	}
 
-	glyphcache = fz_new_glyph_cache(fzctx);
+	glyphcache = fz_new_glyph_cache(ctx);
 
 	colorspace = fz_device_rgb;
 	if (grayscale)
@@ -342,9 +345,14 @@ int main(int argc, char **argv)
 	{
 		filename = argv[fz_optind++];
 
-		code = xps_open_file(fzctx, &doc, filename);
-		if (code)
-			die(fz_error_note(code, "cannot open document: %s", filename));
+		fz_try(ctx)
+		{
+			doc = xps_open_file(ctx, filename);
+		}
+		fz_catch(ctx)
+		{
+			die(fz_error_note(-1, "cannot open document: %s", filename));
+		}
 
 		if (showxml)
 			printf("<document name=\"%s\">\n", filename);
@@ -368,8 +376,8 @@ int main(int argc, char **argv)
 		printf("slowest page %d: %dms\n", timing.maxpage, timing.max);
 	}
 
-	fz_free_glyph_cache(fzctx, glyphcache);
-	fz_free_context(fzctx);
+	fz_free_glyph_cache(ctx, glyphcache);
+	fz_free_context(ctx);
 
 	return 0;
 }