dbfp: refactoring: introduce generic object parser

This commit replaces the manual parsing of the XML location element
with a generic read_object method.  The structure of the element to
parse and the destination of the parsed data is defined in an
object_data array.

1 files changed, 80 insertions, 59 deletions

diff --git a/dbfp.c b/dbfp.c
index 0b41810..05343a1 100644
--- a/dbfp.c
+++ b/dbfp.c
@@ -26,18 +26,24 @@ struct location_data {
 	struct dbfp_location *locations;
 };
 
+struct object_data {
+	const char *name;
+	int (*read)(const char **, size_t, void *);
+	void *value;
+};
+
 static int dbfp_parse(void *contents, size_t len, size_t n, void *data);
 static int dbfp_request(struct dbfp *dbfp, char *service, char *query,
 		XML_Parser parser);
 static int dbfp_url(struct dbfp *dbfp, char *service, char *query, char **url);
 
 static int check_ele_error(const char *name, const char **atts);
-static int read_string(const char **atts, size_t idx, char **str);
-static int read_float(const char **atts, size_t idx, float *f);
+static int read_string(const char **atts, size_t idx, void *value);
+static int read_float(const char **atts, size_t idx, void *value);
+static int read_object_indizes(const char **atts, struct object_data *data,
+		size_t *indizes);
+static int read_object(const char **atts, struct object_data *data);
 
-static int add_location(struct location_data *ld, const char **atts,
-		size_t idx_name, size_t idx_id, size_t idx_lon,
-		size_t idx_lat);
 static void location_start(void *data, const char *name, const char **atts);
 static void location_end(void *data, const char *name);
 
@@ -147,6 +153,7 @@ int dbfp_query_location_name(struct dbfp *dbfp, char *input,
 	*locations = ld.locations;
 
 cleanup:
+	// TODO check whether the elements of ld.locations should be closed
 	if (err)
 		free(ld.locations);
 	if (input_enc)
@@ -235,8 +242,10 @@ static int check_ele_error(const char *name, const char **atts)
 	return 0;
 }
 
-static int read_string(const char **atts, size_t idx, char **str)
+static int read_string(const char **atts, size_t idx, void *value)
 {
+	char **str = (char **)value;
+
 	*str = strdup(atts[idx]);
 	if (!*str)
 		return ENOMEM;
@@ -244,8 +253,9 @@ static int read_string(const char **atts, size_t idx, char **str)
 	return 0;
 }
 
-static int read_float(const char **atts, size_t idx, float *f)
+static int read_float(const char **atts, size_t idx, void *value)
 {
+	float *f = (float *)value;
 	char *endptr = NULL;
 
 	errno = 0;
@@ -256,48 +266,58 @@ static int read_float(const char **atts, size_t idx, float *f)
 	return 0;
 }
 
-static int add_location(struct location_data *ld, const char **atts,
-		size_t idx_name, size_t idx_id, size_t idx_lon,
-		size_t idx_lat)
+static int read_object_indizes(const char **atts, struct object_data *data,
+		size_t *indizes)
+{
+	size_t i;
+	size_t j;
+
+	for (i = 0; data[i].name; i++)
+		indizes[i] = 0;
+
+	for (i = 0; atts[i]; i += 2) {
+		for (j = 0; data[j].name; j++) {
+			if (strcmp(atts[i], data[j].name) == 0) {
+				indizes[j] = i + 1;
+				break;
+			}
+		}
+	}
+
+	for (i = 0; data[i].name; i++) {
+		if (!indizes[i])
+			return DBFP_ERROR_STRUCTURE;
+	}
+
+	return 0;
+}
+
+static int read_object(const char **atts, struct object_data *data)
 {
 	int err = 0;
-	char *name = NULL;
-	char *id = NULL;
-	float lon;
-	float lat;
+	size_t i = 0;
+	size_t n = 0;
+	size_t *indizes;
 
-	err = read_string(atts, idx_name, &name);
-	if (err)
-		goto cleanup;
-	err = read_string(atts, idx_id, &id);
-	if (err)
-		goto cleanup;
-	err = read_float(atts, idx_lon, &lon);
-	if (err)
-		goto cleanup;
-	err = read_float(atts, idx_lat, &lat);
+	for (i = 0; data[i].name; i++)
+		n++;
+
+	indizes = malloc(n * sizeof(*indizes));
+	if (!indizes)
+		return ENOMEM;
+
+	err = read_object_indizes(atts, data, indizes);
 	if (err)
 		goto cleanup;
 
-	/* TODO(robin.krahl):  don't give up the old memory if realloc fails */
-	ld->locations = realloc(ld->locations,
-			(ld->n + 1) * sizeof(*ld->locations));
-	if (!ld->locations) {
-		err = ENOMEM;
-		goto cleanup;
+	for (i = 0; data[i].name; i++) {
+		err = data[i].read(atts, indizes[i], data[i].value);
+		if (err)
+			goto cleanup;
 	}
 
-	ld->locations[ld->n].name = name;
-	ld->locations[ld->n].id = id;
-	ld->locations[ld->n].lon = lon;
-	ld->locations[ld->n].lat = lat;
-	ld->n++;
-
 cleanup:
-	if (err) {
-		free(name);
-		free(id);
-	}
+	free(indizes);
 
 	return err;
 }
@@ -307,11 +327,14 @@ static void location_start(void *data, const char *name, const char **atts)
 	int err = 0;
 	struct parse_data *pd = (struct parse_data *)data;
 	struct location_data *ld = (struct location_data *)pd->data;
-	size_t idx_name = 0;
-	size_t idx_id = 0;
-	size_t idx_lon = 0;
-	size_t idx_lat = 0;
-	size_t i;
+	struct dbfp_location location = { NULL, NULL, 0, 0 };
+	struct object_data od[] = {
+		{ "name", &read_string, &location.name },
+		{ "id", &read_string, &location.id },
+		{ "lon", &read_float, &location.lon },
+		{ "lat", &read_float, &location.lat },
+		{ NULL, NULL, NULL }
+	};
 
 	err = check_ele_error(name, atts);
 	if (err)
@@ -320,27 +343,25 @@ static void location_start(void *data, const char *name, const char **atts)
 	if (strcmp(name, "StopLocation") != 0)
 		goto cleanup;
 
-	for (i = 0; atts[i]; i += 2) {
-		if (strcmp(atts[i], "name") == 0)
-			idx_name = i + 1;
-		else if (strcmp(atts[i], "id") == 0)
-			idx_id = i + 1;
-		else if (strcmp(atts[i], "lon") == 0)
-			idx_lon = i + 1;
-		else if (strcmp(atts[i], "lat") == 0)
-			idx_lat = i + 1;
-	}
+	err = read_object(atts, od);
+	if (err)
+		goto cleanup;
 
-	if (!idx_name || !idx_id || !idx_lon || !idx_lat) {
-		err = DBFP_ERROR_STRUCTURE;
+	ld->locations = realloc(ld->locations,
+			(ld->n + 1) * sizeof(*ld->locations));
+	if (!ld->locations) {
+		err = ENOMEM;
 		goto cleanup;
 	}
 
-	err = add_location(ld, atts, idx_name, idx_id, idx_lon, idx_lat);
+	ld->locations[ld->n] = location;
+	ld->n++;
 
 cleanup:
-	if (err)
+	if (err) {
+		dbfp_location_close(&location);
 		pd->error = err;
+	}
 }
 
 static void location_end(void *data, const char *name)