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.

1 files changed, 97 insertions, 103 deletions

diff --git a/pdf/pdf_type3.c b/pdf/pdf_type3.c
index d2523ae6..c129350a 100644
--- a/pdf/pdf_type3.c
+++ b/pdf/pdf_type3.c
@@ -1,16 +1,15 @@
 #include "fitz.h"
 #include "mupdf.h"
 
-static fz_error
+static void
 pdf_run_glyph_func(void *xref, fz_obj *rdb, fz_buffer *contents, fz_device *dev, fz_matrix ctm)
 {
-	return pdf_run_glyph(xref, rdb, contents, dev, ctm);
+	pdf_run_glyph(xref, rdb, contents, dev, ctm);
 }
 
-fz_error
-pdf_load_type3_font(pdf_font_desc **fontdescp, pdf_xref *xref, fz_obj *rdb, fz_obj *dict)
+pdf_font_desc *
+pdf_load_type3_font(pdf_xref *xref, fz_obj *rdb, fz_obj *dict)
 {
-	fz_error error;
 	char buf[256];
 	char *estrings[256];
 	pdf_font_desc *fontdesc;
@@ -24,136 +23,131 @@ pdf_load_type3_font(pdf_font_desc **fontdescp, pdf_xref *xref, fz_obj *rdb, fz_o
 	fz_matrix matrix;
 	fz_context *ctx = xref->ctx;
 
-	obj = fz_dict_gets(dict, "Name");
-	if (fz_is_name(obj))
-		fz_strlcpy(buf, fz_to_name(obj), sizeof buf);
-	else
-		sprintf(buf, "Unnamed-T3");
+	fz_try(ctx)
+	{
+		obj = fz_dict_gets(dict, "Name");
+		if (fz_is_name(obj))
+			fz_strlcpy(buf, fz_to_name(obj), sizeof buf);
+		else
+			sprintf(buf, "Unnamed-T3");
 
-	fontdesc = pdf_new_font_desc(ctx);
+		fontdesc = pdf_new_font_desc(ctx);
 
-	obj = fz_dict_gets(dict, "FontMatrix");
-	matrix = pdf_to_matrix(ctx, obj);
+		obj = fz_dict_gets(dict, "FontMatrix");
+		matrix = pdf_to_matrix(ctx, obj);
 
-	obj = fz_dict_gets(dict, "FontBBox");
-	bbox = pdf_to_rect(ctx, obj);
+		obj = fz_dict_gets(dict, "FontBBox");
+		bbox = pdf_to_rect(ctx, obj);
 
-	fontdesc->font = fz_new_type3_font(ctx, buf, matrix);
+		fontdesc->font = fz_new_type3_font(ctx, buf, matrix);
 
-	fz_set_font_bbox(fontdesc->font, bbox.x0, bbox.y0, bbox.x1, bbox.y1);
+		fz_set_font_bbox(fontdesc->font, bbox.x0, bbox.y0, bbox.x1, bbox.y1);
 
-	/* Encoding */
+		/* Encoding */
 
-	for (i = 0; i < 256; i++)
-		estrings[i] = NULL;
+		for (i = 0; i < 256; i++)
+			estrings[i] = NULL;
 
-	encoding = fz_dict_gets(dict, "Encoding");
-	if (!encoding)
-	{
-		error = fz_error_make("syntaxerror: Type3 font missing Encoding");
-		goto cleanup;
-	}
+		encoding = fz_dict_gets(dict, "Encoding");
+		if (!encoding)
+		{
+			fz_throw(ctx, "syntaxerror: Type3 font missing Encoding");
+		}
 
-	if (fz_is_name(encoding))
-		pdf_load_encoding(estrings, fz_to_name(encoding));
+		if (fz_is_name(encoding))
+			pdf_load_encoding(estrings, fz_to_name(encoding));
 
-	if (fz_is_dict(encoding))
-	{
-		fz_obj *base, *diff, *item;
+		if (fz_is_dict(encoding))
+		{
+			fz_obj *base, *diff, *item;
 
-		base = fz_dict_gets(encoding, "BaseEncoding");
-		if (fz_is_name(base))
-			pdf_load_encoding(estrings, fz_to_name(base));
+			base = fz_dict_gets(encoding, "BaseEncoding");
+			if (fz_is_name(base))
+				pdf_load_encoding(estrings, fz_to_name(base));
 
-		diff = fz_dict_gets(encoding, "Differences");
-		if (fz_is_array(diff))
-		{
-			n = fz_array_len(diff);
-			k = 0;
-			for (i = 0; i < n; i++)
+			diff = fz_dict_gets(encoding, "Differences");
+			if (fz_is_array(diff))
 			{
-				item = fz_array_get(diff, i);
-				if (fz_is_int(item))
-					k = fz_to_int(item);
-				if (fz_is_name(item))
-					estrings[k++] = fz_to_name(item);
-				if (k < 0) k = 0;
-				if (k > 255) k = 255;
+				n = fz_array_len(diff);
+				k = 0;
+				for (i = 0; i < n; i++)
+				{
+					item = fz_array_get(diff, i);
+					if (fz_is_int(item))
+						k = fz_to_int(item);
+					if (fz_is_name(item))
+						estrings[k++] = fz_to_name(item);
+					if (k < 0) k = 0;
+					if (k > 255) k = 255;
+				}
 			}
 		}
-	}
 
-	fontdesc->encoding = pdf_new_identity_cmap(ctx, 0, 1);
+		fontdesc->encoding = pdf_new_identity_cmap(ctx, 0, 1);
 
-	error = pdf_load_to_unicode(fontdesc, xref, estrings, NULL, fz_dict_gets(dict, "ToUnicode"));
-	if (error)
-		goto cleanup;
+		pdf_load_to_unicode(fontdesc, xref, estrings, NULL, fz_dict_gets(dict, "ToUnicode"));
 
-	/* Widths */
+		/* Widths */
 
-	pdf_set_default_hmtx(fontdesc, 0);
+		pdf_set_default_hmtx(fontdesc, 0);
 
-	first = fz_to_int(fz_dict_gets(dict, "FirstChar"));
-	last = fz_to_int(fz_dict_gets(dict, "LastChar"));
+		first = fz_to_int(fz_dict_gets(dict, "FirstChar"));
+		last = fz_to_int(fz_dict_gets(dict, "LastChar"));
 
-	widths = fz_dict_gets(dict, "Widths");
-	if (!widths)
-	{
-		error = fz_error_make("syntaxerror: Type3 font missing Widths");
-		goto cleanup;
-	}
+		widths = fz_dict_gets(dict, "Widths");
+		if (!widths)
+		{
+			fz_throw(ctx, "syntaxerror: Type3 font missing Widths");
+		}
 
-	for (i = first; i <= last; i++)
-	{
-		float w = fz_to_real(fz_array_get(widths, i - first));
-		w = fontdesc->font->t3matrix.a * w * 1000;
-		fontdesc->font->t3widths[i] = w * 0.001f;
-		pdf_add_hmtx(ctx, fontdesc, i, i, w);
-	}
+		for (i = first; i <= last; i++)
+		{
+			float w = fz_to_real(fz_array_get(widths, i - first));
+			w = fontdesc->font->t3matrix.a * w * 1000;
+			fontdesc->font->t3widths[i] = w * 0.001f;
+			pdf_add_hmtx(ctx, fontdesc, i, i, w);
+		}
 
-	pdf_end_hmtx(fontdesc);
+		pdf_end_hmtx(fontdesc);
 
-	/* Resources -- inherit page resources if the font doesn't have its own */
+		/* Resources -- inherit page resources if the font doesn't have its own */
 
-	fontdesc->font->t3resources = fz_dict_gets(dict, "Resources");
-	if (!fontdesc->font->t3resources)
-		fontdesc->font->t3resources = rdb;
-	if (fontdesc->font->t3resources)
-		fz_keep_obj(fontdesc->font->t3resources);
-	if (!fontdesc->font->t3resources)
-		fz_warn(ctx, "no resource dictionary for type 3 font!");
+		fontdesc->font->t3resources = fz_dict_gets(dict, "Resources");
+		if (!fontdesc->font->t3resources)
+			fontdesc->font->t3resources = rdb;
+		if (fontdesc->font->t3resources)
+			fz_keep_obj(fontdesc->font->t3resources);
+		if (!fontdesc->font->t3resources)
+			fz_warn(ctx, "no resource dictionary for type 3 font!");
 
-	fontdesc->font->t3xref = xref;
-	fontdesc->font->t3run = pdf_run_glyph_func;
+		fontdesc->font->t3xref = xref;
+		fontdesc->font->t3run = pdf_run_glyph_func;
 
-	/* CharProcs */
+		/* CharProcs */
 
-	charprocs = fz_dict_gets(dict, "CharProcs");
-	if (!charprocs)
-	{
-		error = fz_error_make("syntaxerror: Type3 font missing CharProcs");
-		goto cleanup;
-	}
+		charprocs = fz_dict_gets(dict, "CharProcs");
+		if (!charprocs)
+		{
+			fz_throw(ctx, "syntaxerror: Type3 font missing CharProcs");
+		}
 
-	for (i = 0; i < 256; i++)
-	{
-		if (estrings[i])
+		for (i = 0; i < 256; i++)
 		{
-			obj = fz_dict_gets(charprocs, estrings[i]);
-			if (pdf_is_stream(xref, fz_to_num(obj), fz_to_gen(obj)))
+			if (estrings[i])
 			{
-				error = pdf_load_stream(&fontdesc->font->t3procs[i], xref, fz_to_num(obj), fz_to_gen(obj));
-				if (error)
-					goto cleanup;
+				obj = fz_dict_gets(charprocs, estrings[i]);
+				if (pdf_is_stream(xref, fz_to_num(obj), fz_to_gen(obj)))
+				{
+					fontdesc->font->t3procs[i] = pdf_load_stream(xref, fz_to_num(obj), fz_to_gen(obj));
+				}
 			}
 		}
 	}
-
-	*fontdescp = fontdesc;
-	return fz_okay;
-
-cleanup:
-	fz_drop_font(ctx, fontdesc->font);
-	fz_free(ctx, fontdesc);
-	return fz_error_note(error, "cannot load type3 font (%d %d R)", fz_to_num(dict), fz_to_gen(dict));
+	fz_catch(ctx)
+	{
+		fz_drop_font(ctx, fontdesc->font);
+		fz_free(ctx, fontdesc);
+		fz_throw(ctx, "cannot load type3 font (%d %d R)", fz_to_num(dict), fz_to_gen(dict));
+	}
+	return fontdesc;
 }