1 files changed, 96 insertions, 0 deletions
diff --git a/libcoopgamma_check_error__.c b/libcoopgamma_check_error__.c
new file mode 100644
index 0000000..44fb8b7
--- /dev/null
+++ b/libcoopgamma_check_error__.c
@@ -0,0 +1,96 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Check whether the server sent an error, if so copy it to `ctx`
+ * 
+ * This function will also reports EBADMSG if the message ID
+ * that the message is a response to does not match the request
+ * information, or if it is missing
+ * 
+ * @param   ctx    The state of the library, must be connected
+ * @param   async  Information about the request
+ * @return         1 if the server sent an error (even indicating success),
+ *                 0 on success, -1 on failure. Information about failure
+ *                 is copied `ctx`.
+ */
+int
+libcoopgamma_check_error__(libcoopgamma_context_t *restrict ctx, libcoopgamma_async_context_t *restrict async)
+{
+	char temp[3 * sizeof(uint64_t) + 1];
+	size_t old_tail = ctx->inbound_tail;
+	char *line;
+	char *value;
+	int command_ok = 0;
+	int have_in_response_to = 0;
+	int have_error = 0;
+	int bad = 0;
+	char *payload;
+	size_t n;
+
+	for (;;) {
+		line = libcoopgamma_next_header__(ctx);
+		value = &strchr(line, ':')[2U];
+		if (!*line) {
+			break;
+		} else if (!strcmp(line, "Command: error")) {
+			command_ok = 1;
+		} else if (strstr(line, "In response to: ") == line) {
+			uint32_t id = (uint32_t)atol(value);
+			have_in_response_to = 1 + !!have_in_response_to;
+			if (id != async->message_id) {
+				bad = 1;
+			} else {
+				sprintf(temp, "%" PRIu32, id);
+				if (strcmp(value, temp))
+					bad = 1;
+			}
+		} else if (strstr(line, "Error: ") == line) {
+			have_error = 1 + !!have_error;
+			ctx->error.server_side = 1;
+			ctx->error.custom = (strstr(value, "custom") == value);
+			if (ctx->error.custom) {
+				if (value[6] == '\0') {
+					ctx->error.number = 0;
+					continue;
+				} else if (value[6] != ' ') {
+					bad = 1;
+					continue;
+				}
+				value += 7;
+			}
+			ctx->error.number = (uint64_t)atoll(value);
+			sprintf(temp, "%" PRIu64, ctx->error.number);
+			if (strcmp(value, temp))
+				bad = 1;
+		}
+	}
+
+	if (!command_ok) {
+		ctx->inbound_tail = old_tail;
+		return 0;
+	}
+
+	payload = libcoopgamma_next_payload__(ctx, &n);
+	if (payload) {
+		if (memchr(payload, '\0', n) || payload[n - 1U] != '\n')
+			goto badmsg;
+		ctx->error.description = malloc(n);
+		if (ctx->error.description == NULL)
+			goto fail;
+		memcpy(ctx->error.description, payload, n - 1U);
+		ctx->error.description[n - 1U] = '\0';
+	}
+
+	if (bad || have_in_response_to != 1 || have_error != 1)
+		goto badmsg;
+
+	return 1;
+
+badmsg:
+	errno = EBADMSG;
+fail:
+	copy_errno(ctx);
+	return -1;
+}