MINOR: config: add a function to indent error messages

Bind parsers may return multiple errors, so let's make use of a new function
to re-indent multi-line error messages so that they're all reported in their
context.

diff --git a/include/common/standard.h b/include/common/standard.h
index 93b9e363d2d42a2d7e504fdb93c21ea7d59e9c75..2d67faf6fe41edc68f84fdc9119cf4aca3bea0c0 100644 (file)
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -706,6 +706,15 @@ char *gmt2str_log(char *dst, struct tm *tm, size_t size);
 char *memprintf(char **out, const char *format, ...)
        __attribute__ ((format(printf, 2, 3)));
 
+/* Used to add <level> spaces before each line of <out>, unless there is only one line.
+ * The input argument is automatically freed and reassigned. The result will have to be
+ * freed by the caller.
+ * Example of use :
+ *   parse(cmd, &err); (callee: memprintf(&err, ...))
+ *   fprintf(stderr, "Parser said: %s\n", indent_error(&err));
+ *   free(err);
+ */
+char *indent_msg(char **out, int level);
 
 /* debugging macro to emit messages using write() on fd #-1 so that strace sees
  * them.

diff --git a/src/standard.c b/src/standard.c
index e7bc070008e043366e636fe929c8cae40c449771..31f4ddd6fb27d58767dceed7594964853885bdc1 100644 (file)
--- a/src/standard.c
+++ b/src/standard.c
@@ -1834,6 +1834,74 @@ char *memprintf(char **out, const char *format, ...)
        return ret;
 }
 
+/* Used to add <level> spaces before each line of <out>, unless there is only one line.
+ * The input argument is automatically freed and reassigned. The result will have to be
+ * freed by the caller.
+ * Example of use :
+ *   parse(cmd, &err); (callee: memprintf(&err, ...))
+ *   fprintf(stderr, "Parser said: %s\n", indent_error(&err));
+ *   free(err);
+ */
+char *indent_msg(char **out, int level)
+{
+       char *ret, *in, *p;
+       int needed = 0;
+       int lf = 0;
+       int lastlf = 0;
+       int len;
+
+       in = *out - 1;
+       while ((in = strchr(in + 1, '\n')) != NULL) {
+               lastlf = in - *out;
+               lf++;
+       }
+
+       if (!lf) /* single line, no LF, return it as-is */
+               return *out;
+
+       len = strlen(*out);
+
+       if (lf == 1 && lastlf == len - 1) {
+               /* single line, LF at end, strip it and return as-is */
+               (*out)[lastlf] = 0;
+               return *out;
+       }
+
+       /* OK now we have at least one LF, we need to process the whole string
+        * as a multi-line string. What we'll do :
+        *   - prefix with an LF if there is none
+        *   - add <level> spaces before each line
+        * This means at most ( 1 + level + (len-lf) + lf*<1+level) ) =
+        *   1 + level + len + lf * level = 1 + level * (lf + 1) + len.
+        */
+
+       needed = 1 + level * (lf + 1) + len + 1;
+       p = ret = malloc(needed);
+       in = *out;
+
+       /* skip initial LFs */
+       while (*in == '\n')
+               in++;
+
+       /* copy each line, prefixed with LF and <level> spaces, and without the trailing LF */
+       while (*in) {
+               *p++ = '\n';
+               memset(p, ' ', level);
+               p += level;
+               do {
+                       *p++ = *in++;
+               } while (*in && *in != '\n');
+               if (*in)
+                       in++;
+       }
+       *p = 0;
+
+       free(*out);
+       *out = ret;
+
+       return ret;
+}
+
 /*
  * Local variables:
  *  c-indent-level: 8