agerror.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include <cgraph/cghdr.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <util/agxbuf.h>
#include <util/gv_ctype.h>
#include <util/gv_math.h>
#include <util/streq.h>
 
static agerrlevel_t agerrno;             /* Last error level */
static agerrlevel_t agerrlevel = AGWARN; /* Report errors >= agerrlevel */
static int agmaxerr;
 
static agxbuf last;         
static agusererrf usererrf; /* User-set error function */
 
agusererrf agseterrf(agusererrf newf) {
  agusererrf oldf = usererrf;
  usererrf = newf;
  return oldf;
}
 
agerrlevel_t agseterr(agerrlevel_t lvl) {
  agerrlevel_t oldv = agerrlevel;
  agerrlevel = lvl;
  return oldv;
}
 
char *aglasterr(void) {
  // Extract a heap-allocated copy of the last message. Note that this resets
  // `last` to an empty buffer ready to be written to again.
  char *buf = agxbdisown(&last);
 
  // store the message back again so multiple calls to `aglasterr` can be made
  // without losing the last error
  agxbput(&last, buf);
 
  // was there no last message?
  if (streq(buf, "")) {
    free(buf);
    return NULL;
  }
 
  return buf;
}
 
static int default_usererrf(char *message) {
  // `fputs`, escaping characters that may interfere with a terminal
  for (const char *p = message; *p != '\0'; ++p) {
 
    if (gv_iscntrl(*p) && !gv_isspace(*p)) {
      const int rc = fprintf(stderr, "\\%03o", (unsigned)*p);
      if (rc < 0) {
        return rc;
      }
      continue;
    }
 
    const int rc = putc(*p, stderr);
    if (rc < 0) {
      return rc;
    }
  }
  return 0;
}
 
static void out(agerrlevel_t level, const char *fmt, va_list args) {
  // find out how much space we need to construct this string
  size_t bufsz;
  {
    va_list args2;
    va_copy(args2, args);
    int rc = vsnprintf(NULL, 0, fmt, args2);
    va_end(args2);
    if (rc < 0) {
      fprintf(stderr, "%s: vsnprintf failure\n", __func__);
      return;
    }
    bufsz = (size_t)rc + 1; // account for NUL terminator
  }
 
  // allocate a buffer for the string
  char *buf = malloc(bufsz);
  if (buf == NULL) {
    fprintf(stderr, "%s: could not allocate memory\n", __func__);
    return;
  }
 
  // determine how errors are to be reported
  const agusererrf errf = usererrf ? usererrf : default_usererrf;
 
  if (level != AGPREV) {
    (void)errf(level == AGERR ? "Error" : "Warning");
    (void)errf(": ");
  }
 
  // construct the full error in our buffer
  int rc = vsnprintf(buf, bufsz, fmt, args);
  if (rc < 0) {
    free(buf);
    fprintf(stderr, "%s: vsnprintf failure\n", __func__);
    return;
  }
 
  // yield our constructed error
  (void)errf(buf);
 
  free(buf);
}
 
static int agerr_va(agerrlevel_t level, const char *fmt, va_list args) {
  agerrlevel_t lvl;
 
  /* Use previous error level if continuation message;
   * Convert AGMAX to AGERROR;
   * else use input level
   */
  lvl = (level == AGPREV ? agerrno : (level == AGMAX) ? AGERR : level);
 
  /* store this error level */
  agerrno = lvl;
  agmaxerr = imax(agmaxerr, (int)agerrno);
 
  /* We report all messages whose level is bigger than the user set agerrlevel
   * Setting agerrlevel to AGMAX turns off immediate error reporting.
   */
  if (lvl >= agerrlevel) {
    out(level, fmt, args);
    return 0;
  }
 
  if (level != AGPREV)
    agxbclear(&last);
  vagxbprint(&last, fmt, args);
  return 0;
}
 
int agerr(agerrlevel_t level, const char *fmt, ...) {
  va_list args;
  int ret;
 
  va_start(args, fmt);
  ret = agerr_va(level, fmt, args);
  va_end(args);
  return ret;
}
 
void agerrorf(const char *fmt, ...) {
  va_list args;
 
  va_start(args, fmt);
  agerr_va(AGERR, fmt, args);
  va_end(args);
}
 
void agwarningf(const char *fmt, ...) {
  va_list args;
 
  va_start(args, fmt);
  agerr_va(AGWARN, fmt, args);
  va_end(args);
}
 
int agerrors(void) { return agmaxerr; }
 
int agreseterrors(void) {
  int rc = agmaxerr;
  agmaxerr = 0;
  return rc;
}