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, 114 insertions, 171 deletions

diff --git a/pdf/pdf_cmap_parse.c b/pdf/pdf_cmap_parse.c
index d048271f..4dcc76c5 100644
--- a/pdf/pdf_cmap_parse.c
+++ b/pdf/pdf_cmap_parse.c
@@ -48,65 +48,54 @@ pdf_code_from_string(char *buf, int len)
 	return a;
 }
 
-static fz_error
-pdf_lex_cmap(int *tok, fz_stream *file, char *buf, int n, int *sl)
+static int
+pdf_lex_cmap(fz_stream *file, char *buf, int n, int *sl)
 {
-	fz_error error;
+	int tok = pdf_lex(file, buf, n, sl);
 
-	error = pdf_lex(tok, file, buf, n, sl);
-	if (error)
-		return fz_error_note(error, "cannot parse cmap token");
+	/* RJW: Lost debugging here: "cannot parse cmap token" */
 
-	if (*tok == PDF_TOK_KEYWORD)
-		*tok = pdf_cmap_token_from_keyword(buf);
+	if (tok == PDF_TOK_KEYWORD)
+		tok = pdf_cmap_token_from_keyword(buf);
 
-	return fz_okay;
+	return tok;
 }
 
-static fz_error
+static void
 pdf_parse_cmap_name(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
 
-	error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-	if (error)
-		return fz_error_note(error, "syntaxerror in cmap");
+	tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+	/* RJW: Lost debugging: "syntaxerror in cmap" */
 
 	if (tok == PDF_TOK_NAME)
 		fz_strlcpy(cmap->cmap_name, buf, sizeof(cmap->cmap_name));
 	else
 		fz_warn(file->ctx, "expected name after CMapName in cmap");
-
-	return fz_okay;
 }
 
-static fz_error
+static void
 pdf_parse_wmode(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
 
-	error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-	if (error)
-		return fz_error_note(error, "syntaxerror in cmap");
+	tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+	/* RJW: Lost debugging: "syntaxerror in cmap" */
 
 	if (tok == PDF_TOK_INT)
 		pdf_set_wmode(cmap, atoi(buf));
 	else
 		fz_warn(file->ctx, "expected integer after WMode in cmap");
-
-	return fz_okay;
 }
 
-static fz_error
+static void
 pdf_parse_codespace_range(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -114,19 +103,17 @@ pdf_parse_codespace_range(pdf_cmap *cmap, fz_stream *file)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: Lost debugging: "syntaxerror in cmap" */
 
 		if (tok == TOK_END_CODESPACE_RANGE)
-			return fz_okay;
+			return;
 
 		else if (tok == PDF_TOK_STRING)
 		{
 			lo = pdf_code_from_string(buf, len);
-			error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-			if (error)
-				return fz_error_note(error, "syntaxerror in cmap");
+			tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+			/* RJW: Lost debugging: "syntaxerror in cmap" */
 			if (tok == PDF_TOK_STRING)
 			{
 				hi = pdf_code_from_string(buf, len);
@@ -138,13 +125,12 @@ pdf_parse_codespace_range(pdf_cmap *cmap, fz_stream *file)
 		else break;
 	}
 
-	return fz_error_make("expected string or endcodespacerange");
+	fz_throw(file->ctx, "expected string or endcodespacerange");
 }
 
-static fz_error
+static void
 pdf_parse_cid_range(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -152,31 +138,28 @@ pdf_parse_cid_range(pdf_cmap *cmap, fz_stream *file)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: Lost debugging: "syntaxerror in cmap" */
 
 		if (tok == TOK_END_CID_RANGE)
-			return fz_okay;
+			return;
 
 		else if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string or endcidrange");
+			fz_throw(file->ctx, "expected string or endcidrange");
 
 		lo = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: Lost debugging: "syntaxerror in cmap" */
 		if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string");
+			fz_throw(file->ctx, "expected string");
 
 		hi = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: Lost debugging: "syntaxerror in cmap" */
 		if (tok != PDF_TOK_INT)
-			return fz_error_make("expected integer");
+			fz_throw(file->ctx, "expected integer");
 
 		dst = atoi(buf);
 
@@ -184,10 +167,9 @@ pdf_parse_cid_range(pdf_cmap *cmap, fz_stream *file)
 	}
 }
 
-static fz_error
+static void
 pdf_parse_cid_char(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -195,23 +177,22 @@ pdf_parse_cid_char(pdf_cmap *cmap, fz_stream *file)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 
 		if (tok == TOK_END_CID_CHAR)
-			return fz_okay;
+			return;
 
 		else if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string or endcidchar");
+			fz_throw(file->ctx, "expected string or endcidchar");
 
 		src = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
+
 		if (tok != PDF_TOK_INT)
-			return fz_error_make("expected integer");
+			fz_throw(file->ctx, "expected integer");
 
 		dst = atoi(buf);
 
@@ -219,10 +200,9 @@ pdf_parse_cid_char(pdf_cmap *cmap, fz_stream *file)
 	}
 }
 
-static fz_error
+static void
 pdf_parse_bf_range_array(pdf_cmap *cmap, fz_stream *file, int lo, int hi)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -231,16 +211,15 @@ pdf_parse_bf_range_array(pdf_cmap *cmap, fz_stream *file, int lo, int hi)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 
 		if (tok == PDF_TOK_CLOSE_ARRAY)
-			return fz_okay;
+			return;
 
 		/* Note: does not handle [ /Name /Name ... ] */
 		else if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string or ]");
+			fz_throw(file->ctx, "expected string or ]");
 
 		if (len / 2)
 		{
@@ -254,10 +233,9 @@ pdf_parse_bf_range_array(pdf_cmap *cmap, fz_stream *file, int lo, int hi)
 	}
 }
 
-static fz_error
+static void
 pdf_parse_bf_range(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -265,29 +243,26 @@ pdf_parse_bf_range(pdf_cmap *cmap, fz_stream *file)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 
 		if (tok == TOK_END_BF_RANGE)
-			return fz_okay;
+			return;
 
 		else if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string or endbfrange");
+			fz_throw(file->ctx, "expected string or endbfrange");
 
 		lo = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 		if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string");
+			fz_throw(file->ctx, "expected string");
 
 		hi = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 
 		if (tok == PDF_TOK_STRING)
 		{
@@ -318,22 +293,20 @@ pdf_parse_bf_range(pdf_cmap *cmap, fz_stream *file)
 
 		else if (tok == PDF_TOK_OPEN_ARRAY)
 		{
-			error = pdf_parse_bf_range_array(cmap, file, lo, hi);
-			if (error)
-				return fz_error_note(error, "cannot map bfrange");
+			pdf_parse_bf_range_array(cmap, file, lo, hi);
+			/* RJW: "cannot map bfrange" */
 		}
 
 		else
 		{
-			return fz_error_make("expected string or array or endbfrange");
+			fz_throw(file->ctx, "expected string or array or endbfrange");
 		}
 	}
 }
 
-static fz_error
+static void
 pdf_parse_bf_char(pdf_cmap *cmap, fz_stream *file)
 {
-	fz_error error;
 	char buf[256];
 	int tok;
 	int len;
@@ -343,24 +316,22 @@ pdf_parse_bf_char(pdf_cmap *cmap, fz_stream *file)
 
 	while (1)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 
 		if (tok == TOK_END_BF_CHAR)
-			return fz_okay;
+			return;
 
 		else if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string or endbfchar");
+			fz_throw(file->ctx, "expected string or endbfchar");
 
 		src = pdf_code_from_string(buf, len);
 
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
-			return fz_error_note(error, "syntaxerror in cmap");
+		tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
+		/* RJW: "syntaxerror in cmap" */
 		/* Note: does not handle /dstName */
 		if (tok != PDF_TOK_STRING)
-			return fz_error_make("expected string");
+			fz_throw(file->ctx, "expected string");
 
 		if (len / 2)
 		{
@@ -371,120 +342,92 @@ pdf_parse_bf_char(pdf_cmap *cmap, fz_stream *file)
 	}
 }
 
-fz_error
-pdf_parse_cmap(pdf_cmap **cmapp, fz_stream *file)
+pdf_cmap *
+pdf_parse_cmap(fz_stream *file)
 {
-	fz_error error;
 	pdf_cmap *cmap;
 	char key[64];
 	char buf[256];
 	int tok;
 	int len;
+	const char *where;
+	fz_context *ctx = file->ctx;
 
-	cmap = pdf_new_cmap(file->ctx);
+	cmap = pdf_new_cmap(ctx);
 
 	strcpy(key, ".notdef");
 
-	while (1)
+	fz_try(ctx)
 	{
-		error = pdf_lex_cmap(&tok, file, buf, sizeof buf, &len);
-		if (error)
+		while (1)
 		{
-			error = fz_error_note(error, "syntaxerror in cmap");
-			goto cleanup;
-		}
+			where = "";
+			tok = pdf_lex_cmap(file, buf, sizeof buf, &len);
 
-		if (tok == PDF_TOK_EOF || tok == TOK_END_CMAP)
-			break;
+			if (tok == PDF_TOK_EOF || tok == TOK_END_CMAP)
+				break;
 
-		else if (tok == PDF_TOK_NAME)
-		{
-			if (!strcmp(buf, "CMapName"))
+			else if (tok == PDF_TOK_NAME)
 			{
-				error = pdf_parse_cmap_name(cmap, file);
-				if (error)
+				if (!strcmp(buf, "CMapName"))
 				{
-					error = fz_error_note(error, "syntaxerror in cmap after CMapName");
-					goto cleanup;
+					where = " after CMapName";
+					pdf_parse_cmap_name(cmap, file);
 				}
-			}
-			else if (!strcmp(buf, "WMode"))
-			{
-				error = pdf_parse_wmode(cmap, file);
-				if (error)
+				else if (!strcmp(buf, "WMode"))
 				{
-					error = fz_error_note(error, "syntaxerror in cmap after WMode");
-					goto cleanup;
+					where = " after WMode";
+					pdf_parse_wmode(cmap, file);
 				}
+				else
+					fz_strlcpy(key, buf, sizeof key);
 			}
-			else
-				fz_strlcpy(key, buf, sizeof key);
-		}
 
-		else if (tok == TOK_USECMAP)
-		{
-			fz_strlcpy(cmap->usecmap_name, key, sizeof(cmap->usecmap_name));
-		}
+			else if (tok == TOK_USECMAP)
+			{
+				fz_strlcpy(cmap->usecmap_name, key, sizeof(cmap->usecmap_name));
+			}
 
-		else if (tok == TOK_BEGIN_CODESPACE_RANGE)
-		{
-			error = pdf_parse_codespace_range(cmap, file);
-			if (error)
+			else if (tok == TOK_BEGIN_CODESPACE_RANGE)
 			{
-				error = fz_error_note(error, "syntaxerror in cmap codespacerange");
-				goto cleanup;
+				where = " codespacerange";
+				pdf_parse_codespace_range(cmap, file);
 			}
-		}
 
-		else if (tok == TOK_BEGIN_BF_CHAR)
-		{
-			error = pdf_parse_bf_char(cmap, file);
-			if (error)
+			else if (tok == TOK_BEGIN_BF_CHAR)
 			{
-				error = fz_error_note(error, "syntaxerror in cmap bfchar");
-				goto cleanup;
+				where = " bfchar";
+				pdf_parse_bf_char(cmap, file);
 			}
-		}
 
-		else if (tok == TOK_BEGIN_CID_CHAR)
-		{
-			error = pdf_parse_cid_char(cmap, file);
-			if (error)
+			else if (tok == TOK_BEGIN_CID_CHAR)
 			{
-				error = fz_error_note(error, "syntaxerror in cmap cidchar");
-				goto cleanup;
+				where = " cidchar";
+				pdf_parse_cid_char(cmap, file);
 			}
-		}
 
-		else if (tok == TOK_BEGIN_BF_RANGE)
-		{
-			error = pdf_parse_bf_range(cmap, file);
-			if (error)
+			else if (tok == TOK_BEGIN_BF_RANGE)
 			{
-				error = fz_error_note(error, "syntaxerror in cmap bfrange");
-				goto cleanup;
+				where = " bfrange";
+				pdf_parse_bf_range(cmap, file);
 			}
-		}
 
-		else if (tok == TOK_BEGIN_CID_RANGE)
-		{
-			error = pdf_parse_cid_range(cmap, file);
-			if (error)
+			else if (tok == TOK_BEGIN_CID_RANGE)
 			{
-				error = fz_error_note(error, "syntaxerror in cmap cidrange");
-				goto cleanup;
+				where = "cidrange";
+				pdf_parse_cid_range(cmap, file);
 			}
+
+			/* ignore everything else */
 		}
 
-		/* ignore everything else */
+		pdf_sort_cmap(file->ctx, cmap);
+	}
+	fz_catch(ctx)
+	{
+		pdf_drop_cmap(file->ctx, cmap);
+		fz_throw(ctx, "syntaxerror in cmap%s", where);
 	}
 
-	pdf_sort_cmap(file->ctx, cmap);
-
-	*cmapp = cmap;
-	return fz_okay;
-
-cleanup:
-	pdf_drop_cmap(file->ctx, cmap);
-	return error; /* already rethrown */
+	return cmap;
 }