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, 11 insertions, 15 deletions

diff --git a/fitz/res_pixmap.c b/fitz/res_pixmap.c
index a34933f5..471dcc72 100644
--- a/fitz/res_pixmap.c
+++ b/fitz/res_pixmap.c
@@ -293,19 +293,19 @@ fz_gamma_pixmap(fz_pixmap *pix, float gamma)
  * Write pixmap to PNM file (without alpha channel)
  */
 
-fz_error
-fz_write_pnm(fz_pixmap *pixmap, char *filename)
+void
+fz_write_pnm(fz_context *ctx, fz_pixmap *pixmap, char *filename)
 {
 	FILE *fp;
 	unsigned char *p;
 	int len;
 
 	if (pixmap->n != 1 && pixmap->n != 2 && pixmap->n != 4)
-		return fz_error_make("pixmap must be grayscale or rgb to write as pnm");
+		fz_throw(ctx, "pixmap must be grayscale or rgb to write as pnm");
 
 	fp = fopen(filename, "wb");
 	if (!fp)
-		return fz_error_make("cannot open file '%s': %s", filename, strerror(errno));
+		fz_throw(ctx, "cannot open file '%s': %s", filename, strerror(errno));
 
 	if (pixmap->n == 1 || pixmap->n == 2)
 		fprintf(fp, "P5\n");
@@ -340,15 +340,14 @@ fz_write_pnm(fz_pixmap *pixmap, char *filename)
 	}
 
 	fclose(fp);
-	return fz_okay;
 }
 
 /*
  * Write pixmap to PAM file (with or without alpha channel)
  */
 
-fz_error
-fz_write_pam(fz_pixmap *pixmap, char *filename, int savealpha)
+void
+fz_write_pam(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 {
 	unsigned char *sp;
 	int y, w, k;
@@ -361,7 +360,7 @@ fz_write_pam(fz_pixmap *pixmap, char *filename, int savealpha)
 
 	fp = fopen(filename, "wb");
 	if (!fp)
-		return fz_error_make("cannot open file '%s': %s", filename, strerror(errno));
+		fz_throw(ctx, "cannot open file '%s': %s", filename, strerror(errno));
 
 	fprintf(fp, "P7\n");
 	fprintf(fp, "WIDTH %d\n", pixmap->w);
@@ -392,8 +391,6 @@ fz_write_pam(fz_pixmap *pixmap, char *filename, int savealpha)
 	}
 
 	fclose(fp);
-
-	return fz_okay;
 }
 
 /*
@@ -430,7 +427,7 @@ static void putchunk(char *tag, unsigned char *data, int size, FILE *fp)
 	put32(sum, fp);
 }
 
-fz_error
+void
 fz_write_png(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 {
 	static const unsigned char pngsig[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
@@ -443,7 +440,7 @@ fz_write_png(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 	int err;
 
 	if (pixmap->n != 1 && pixmap->n != 2 && pixmap->n != 4)
-		return fz_error_make("pixmap must be grayscale or rgb to write as png");
+		fz_throw(ctx, "pixmap must be grayscale or rgb to write as png");
 
 	sn = pixmap->n;
 	dn = pixmap->n;
@@ -488,7 +485,7 @@ fz_write_png(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 	{
 		fz_free(ctx, udata);
 		fz_free(ctx, cdata);
-		return fz_error_make("cannot compress image data");
+		fz_throw(ctx, "cannot compress image data");
 	}
 
 	fp = fopen(filename, "wb");
@@ -496,7 +493,7 @@ fz_write_png(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 	{
 		fz_free(ctx, udata);
 		fz_free(ctx, cdata);
-		return fz_error_make("cannot open file '%s': %s", filename, strerror(errno));
+		fz_throw(ctx, "cannot open file '%s': %s", filename, strerror(errno));
 	}
 
 	big32(head+0, pixmap->w);
@@ -515,5 +512,4 @@ fz_write_png(fz_context *ctx, fz_pixmap *pixmap, char *filename, int savealpha)
 
 	fz_free(ctx, udata);
 	fz_free(ctx, cdata);
-	return fz_okay;
 }