1 files changed, 95 insertions, 0 deletions
diff --git a/examples/dte/error.c b/examples/dte/error.c
new file mode 100644
index 0000000..87831c9
--- /dev/null
+++ b/examples/dte/error.c
@@ -0,0 +1,95 @@
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include "error.h"
+#include "command/run.h"
+#include "config.h"
+#include "util/log.h"
+#include "util/xstdio.h"
+
+static char error_buf[512];
+static unsigned int nr_errors;
+static bool msg_is_error;
+static bool print_errors_to_stderr;
+
+void clear_error(void)
+{
+    error_buf[0] = '\0';
+}
+
+bool error_msg(const char *format, ...)
+{
+    const char *cmd = current_command ? current_command->name : NULL;
+    const char *file = current_config.file;
+    const unsigned int line = current_config.line;
+    const size_t size = sizeof(error_buf);
+    int pos = 0;
+
+    if (file && cmd) {
+        pos = snprintf(error_buf, size, "%s:%u: %s: ", file, line, cmd);
+    } else if (file) {
+        pos = snprintf(error_buf, size, "%s:%u: ", file, line);
+    } else if (cmd) {
+        pos = snprintf(error_buf, size, "%s: ", cmd);
+    }
+
+    if (unlikely(pos < 0)) {
+        // Note: POSIX snprintf(3) *does* set errno on failure (unlike ISO C)
+        LOG_ERRNO("snprintf");
+        pos = 0;
+    }
+
+    if (likely(pos < (size - 3))) {
+        va_list ap;
+        va_start(ap, format);
+        vsnprintf(error_buf + pos, size - pos, format, ap);
+        va_end(ap);
+    } else {
+        LOG_WARNING("no buffer space left for error message");
+    }
+
+    msg_is_error = true;
+    nr_errors++;
+
+    if (print_errors_to_stderr) {
+        xfputs(error_buf, stderr);
+        xfputc('\n', stderr);
+    }
+
+    LOG_INFO("%s", error_buf);
+
+    // Always return false, to allow tail-calling as `return error_msg(...);`
+    // from command handlers, instead of `error_msg(...); return false;`
+    return false;
+}
+
+bool error_msg_errno(const char *prefix)
+{
+    return error_msg("%s: %s", prefix, strerror(errno));
+}
+
+void info_msg(const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    vsnprintf(error_buf, sizeof(error_buf), format, ap);
+    va_end(ap);
+    msg_is_error = false;
+}
+
+const char *get_msg(bool *is_error)
+{
+    *is_error = msg_is_error;
+    return error_buf;
+}
+
+unsigned int get_nr_errors(void)
+{
+    return nr_errors;
+}
+
+void set_print_errors_to_stderr(bool enable)
+{
+    print_errors_to_stderr = enable;
+}