write.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 v2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include "config.h"
 
#include <assert.h>
#include <cgraph/agstrcanon.h>
#include <cgraph/cghdr.h>
#include <ctype.h>
#include <inttypes.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h> /* need sprintf() */
#include <stdlib.h>
#include <util/gv_ctype.h>
#include <util/strcasecmp.h>
 
#define EMPTY(s) (((s) == 0) || (s)[0] == '\0')
 
typedef void iochan_t;
 
static int ioput(Agraph_t *g, iochan_t *ofile, char *str) {
  return AGDISC(g, io)->putstr(ofile, str);
}
 
#define MAX_OUTPUTLINE 128
#define MIN_OUTPUTLINE 60
static int Max_outputline = MAX_OUTPUTLINE;
static Agsym_t *Tailport, *Headport;
 
static Agedge_t *const EDGE_DONE = (Agedge_t *)-1;
 
typedef struct {
  uint64_t *preorder_number; // of a graph or subgraph
  uint64_t
      *node_last_written; // postorder number of subg when node was last written
  Agedge_t **edge;        
  size_t n_edges;         // items in `edges`
  int level;              // indentation level
} info_t;
 
static int write_body(Agraph_t *g, iochan_t *ofile, info_t *info);
 
static info_t before_write(Agraph_t *);
static void after_write(info_t);
 
static int indent(Agraph_t *g, iochan_t *ofile, const info_t info) {
  for (int i = info.level; i > 0; i--) {
    if (ioput(g, ofile, "\t") == EOF) {
      return EOF;
    }
  }
  return 0;
}
 
// alphanumeric, '.', '-', or non-ascii; basically, chars used in unquoted ids
static bool is_id_char(char c) {
  return gv_isalnum(c) || c == '.' || c == '-' || !isascii(c);
}
 
// is the prefix of this string a recognized Graphviz escape sequence?
// https://graphviz.org/docs/attr-types/escString/
static bool is_escape(const char *str) {
  assert(str != NULL);
 
  if (*str != '\\')
    return false;
 
  if (str[1] == 'E')
    return true;
  if (str[1] == 'G')
    return true;
  if (str[1] == 'H')
    return true;
  if (str[1] == 'L')
    return true;
  if (str[1] == 'N')
    return true;
  if (str[1] == 'T')
    return true;
 
  if (str[1] == 'l')
    return true;
  if (str[1] == 'n')
    return true;
  if (str[1] == 'r')
    return true;
 
  if (str[1] == '\\')
    return true;
 
  if (str[1] == '"')
    return true;
 
  return false;
}
 
/* Canonicalize ordinary strings.
 * Assumes buf is large enough to hold output.
 */
static char *agstrcanon_(char *arg, char *buf) {
  char *s, *p;
  char uc;
  int cnt = 0, dotcnt = 0;
  bool needs_quotes = false;
  bool part_of_escape = false;
  bool maybe_num;
  bool backslash_pending = false;
  static const char *tokenlist[] /* must agree with scan.l */
      = {"node", "edge", "strict", "graph", "digraph", "subgraph", NULL};
  const char **tok;
 
  if (EMPTY(arg))
    return "\"\"";
  s = arg;
  p = buf;
  *p++ = '\"';
  uc = *s++;
  maybe_num = gv_isdigit(uc) || uc == '.' || uc == '-';
  while (uc) {
    if (uc == '\"' && !part_of_escape) {
      *p++ = '\\';
      needs_quotes = true;
    } else if (!part_of_escape && is_escape(&s[-1])) {
      needs_quotes = true;
      part_of_escape = true;
    } else if (maybe_num) {
      if (uc == '-') {
        if (cnt) {
          maybe_num = false;
          needs_quotes = true;
        }
      } else if (uc == '.') {
        if (dotcnt++) {
          maybe_num = false;
          needs_quotes = true;
        }
      } else if (!gv_isdigit(uc)) {
        maybe_num = false;
        needs_quotes = true;
      }
      part_of_escape = false;
    } else if (!(gv_isalnum(uc) || uc == '_' || !isascii(uc))) {
      needs_quotes = true;
      part_of_escape = false;
    } else {
      part_of_escape = false;
    }
    *p++ = uc;
    uc = *s++;
    cnt++;
 
    /* If breaking long strings into multiple lines, only allow breaks after a
     * non-id char, not a backslash, where the next char is an id char.
     */
    if (Max_outputline) {
      if (uc && backslash_pending && !(is_id_char(p[-1]) || p[-1] == '\\') &&
          is_id_char(uc)) {
        *p++ = '\\';
        *p++ = '\n';
        needs_quotes = true;
        backslash_pending = false;
        cnt = 0;
      } else if (uc && (cnt >= Max_outputline)) {
        if (!(is_id_char(p[-1]) || p[-1] == '\\') && is_id_char(uc)) {
          *p++ = '\\';
          *p++ = '\n';
          needs_quotes = true;
          cnt = 0;
        } else {
          backslash_pending = true;
        }
      }
    }
  }
  *p++ = '\"';
  *p = '\0';
  if (needs_quotes || (cnt == 1 && (*arg == '.' || *arg == '-')))
    return buf;
 
  /* Use quotes to protect tokens (example, a node named "node") */
  /* It would be great if it were easier to use flex here. */
  for (tok = tokenlist; *tok; tok++)
    if (!strcasecmp(*tok, arg))
      return buf;
  return arg;
}
 
static char *agcanonhtmlstr(const char *arg, char *buf) {
  sprintf(buf, "<%s>", arg);
  return buf;
}
 
char *agstrcanon(char *arg, char *buf) {
  if (aghtmlstr(arg))
    return agcanonhtmlstr(arg, buf);
  else
    return agstrcanon_(arg, buf);
}
 
static int write_canonstr_(Agraph_t *g, iochan_t *ofile, char *str, bool chk) {
 
  // maximum bytes required for canonicalized string
  const size_t required = agstrcanon_bytes(str);
 
  // allocate space to stage the canonicalized string
  char *const scratch = malloc(required);
  if (scratch == NULL) {
    return EOF;
  }
 
  char *const canonicalized =
      chk ? agstrcanon(str, scratch) : agstrcanon_(str, scratch);
  const int rc = ioput(g, ofile, canonicalized);
  free(scratch);
  return rc;
}
 
static int write_canonstr(Agraph_t *g, iochan_t *ofile, char *str, bool known) {
  char *s;
 
  /* str may not have been allocated by agstrdup, so we first need to turn it
   * into a valid refstr
   */
  s = known ? str : agstrdup(g, str);
 
  int r = write_canonstr_(g, ofile, s, true);
 
  if (!known) {
    agstrfree(g, s, false);
  }
  return r;
}
 
static int write_dict(Agraph_t *g, iochan_t *ofile, char *name, Dict_t *dict,
                      bool top, info_t *info) {
  int cnt = 0;
  Agsym_t *sym, *psym;
 
  Dict_t *const view = !top ? dtview(dict, NULL) : NULL;
  for (sym = dtfirst(dict); sym; sym = dtnext(dict, sym)) {
    if (EMPTY(sym->defval) &&
        !sym->print) { /* try to skip empty str (default) */
      if (view == NULL)
        continue; /* no parent */
      psym = dtsearch(view, sym);
      assert(psym);
      if (EMPTY(psym->defval) && psym->print)
        continue; /* also empty in parent */
    }
    if (cnt++ == 0) {
      if (indent(g, ofile, *info) == EOF || ioput(g, ofile, name) == EOF ||
          ioput(g, ofile, " [") == EOF) {
        return EOF;
      }
      info->level++;
    } else {
      if (ioput(g, ofile, ",\n") == EOF || indent(g, ofile, *info) == EOF) {
        return EOF;
      }
    }
    if (write_canonstr(g, ofile, sym->name, true) == EOF ||
        ioput(g, ofile, "=") == EOF ||
        write_canonstr(g, ofile, sym->defval, true) == EOF) {
      return EOF;
    }
  }
  if (cnt > 0) {
    info->level--;
    if (cnt > 1) {
      if (ioput(g, ofile, "\n") == EOF || indent(g, ofile, *info) == EOF) {
        return EOF;
      }
    }
    if (ioput(g, ofile, "];\n") == EOF) {
      return EOF;
    }
  }
  if (!top)
    dtview(dict, view); /* restore previous view */
  return 0;
}
 
static int write_dicts(Agraph_t *g, iochan_t *ofile, bool top, info_t *info) {
  Agdatadict_t *def;
  if ((def = agdatadict(g, false))) {
    if (write_dict(g, ofile, "graph", def->dict.g, top, info) == EOF ||
        write_dict(g, ofile, "node", def->dict.n, top, info) == EOF ||
        write_dict(g, ofile, "edge", def->dict.e, top, info) == EOF) {
      return EOF;
    }
  }
  return 0;
}
 
static int write_hdr(Agraph_t *g, iochan_t *ofile, bool top, info_t *info) {
  char *name, *sep, *kind, *strict;
  bool root = false;
  bool hasName = true;
 
  strict = "";
  if (!top && agparent(g))
    kind = "sub";
  else {
    root = true;
    if (g->desc.directed)
      kind = "di";
    else
      kind = "";
    if (agisstrict(g))
      strict = "strict ";
    Tailport = agattr_text(g, AGEDGE, TAILPORT_ID, NULL);
    Headport = agattr_text(g, AGEDGE, HEADPORT_ID, NULL);
  }
  name = agnameof(g);
  sep = " ";
  if (!name || name[0] == LOCALNAMEPREFIX) {
    sep = name = "";
    hasName = false;
  }
  if (indent(g, ofile, *info) == EOF || ioput(g, ofile, strict) == EOF) {
    return EOF;
  }
 
  /* output "<kind>graph" only for root graphs or graphs with names */
  if (root || hasName) {
    if (ioput(g, ofile, kind) == EOF || ioput(g, ofile, "graph ") == EOF) {
      return EOF;
    }
  }
  if (hasName) {
    if (write_canonstr(g, ofile, name, false) == EOF) {
      return EOF;
    }
  }
  if (ioput(g, ofile, sep) == EOF || ioput(g, ofile, "{\n") == EOF) {
    return EOF;
  }
  info->level++;
  if (write_dicts(g, ofile, top, info) == EOF) {
    return EOF;
  }
  AGATTRWF(g) = true;
  return 0;
}
 
static int write_trl(Agraph_t *g, iochan_t *ofile, info_t *info) {
  info->level--;
  if (indent(g, ofile, *info) == EOF || ioput(g, ofile, "}\n") == EOF) {
    return EOF;
  }
  return 0;
}
 
static bool is_anonymous(Agraph_t *g) {
  assert(g != NULL);
 
  // handle the common case inline for performance
  if (AGDISC(g, id) == &AgIdDisc) {
    // replicate `idprint`
    const IDTYPE id = AGID(g);
    if (id % 2 != 0) {
      return true;
    }
    return *(char *)(uintptr_t)id == LOCALNAMEPREFIX;
  }
 
  const char *const name = agnameof(g);
  return name == NULL || name[0] == LOCALNAMEPREFIX;
}
 
static bool irrelevant_subgraph(Agraph_t *g) {
  int i, n;
  Agattr_t *sdata, *pdata, *rdata;
  Agdatadict_t *dd;
 
  if (!is_anonymous(g))
    return false;
  if ((sdata = agattrrec(g)) && (pdata = agattrrec(agparent(g)))) {
    rdata = agattrrec(agroot(g));
    n = dtsize(rdata->dict);
    for (i = 0; i < n; i++)
      if (sdata->str[i] && pdata->str[i] &&
          strcmp(sdata->str[i], pdata->str[i]))
        return false;
  }
  dd = agdatadict(g, false);
  if (!dd)
    return true;
  if (dtsize(dd->dict.n) > 0 || dtsize(dd->dict.e) > 0)
    return false;
  return true;
}
 
static bool has_no_edges(Agraph_t *g, Agnode_t *n) {
  return agfstin(g, n) == NULL && agfstout(g, n) == NULL;
}
 
static bool not_default_attrs(Agraph_t *g, Agnode_t *n) {
  Agattr_t *data;
  Agsym_t *sym;
 
  (void)g;
  if ((data = agattrrec(n))) {
    for (sym = dtfirst(data->dict); sym; sym = dtnext(data->dict, sym)) {
      if (data->str[sym->id] != sym->defval)
        return true;
    }
  }
  return false;
}
 
static int write_subgs(Agraph_t *g, iochan_t *ofile, info_t *info) {
  Agraph_t *subg;
 
  for (subg = agfstsubg(g); subg; subg = agnxtsubg(subg)) {
    if (irrelevant_subgraph(subg)) {
      write_subgs(subg, ofile, info);
    } else {
      if (write_hdr(subg, ofile, false, info) == EOF ||
          write_body(subg, ofile, info) == EOF ||
          write_trl(subg, ofile, info) == EOF) {
        return EOF;
      }
    }
  }
  return 0;
}
 
static int write_edge_name(Agedge_t *e, iochan_t *ofile, bool terminate,
                           info_t *info) {
  char *p;
  Agraph_t *g;
 
  p = agnameof(e);
  g = agraphof(e);
  if (!EMPTY(p)) {
    if (!terminate) {
      info->level++;
    }
    if (ioput(g, ofile, "\t[key=") == EOF ||
        write_canonstr(g, ofile, p, false) == EOF) {
      return EOF;
    }
    if (terminate) {
      if (ioput(g, ofile, "]") == EOF) {
        return EOF;
      }
    }
    return 1;
  }
  return 0;
}
 
static int write_nondefault_attrs(void *obj, iochan_t *ofile, Dict_t *defdict,
                                  info_t *info) {
  Agattr_t *data;
  Agsym_t *sym;
  Agraph_t *g;
  int cnt = 0;
 
  if (AGTYPE(obj) == AGINEDGE || AGTYPE(obj) == AGOUTEDGE) {
    const int rv = write_edge_name(obj, ofile, false, info);
    if (rv == EOF) {
      return EOF;
    }
    if (rv)
      cnt++;
  }
  data = agattrrec(obj);
  g = agraphof(obj);
  if (data)
    for (sym = dtfirst(defdict); sym; sym = dtnext(defdict, sym)) {
      if (AGTYPE(obj) == AGINEDGE || AGTYPE(obj) == AGOUTEDGE) {
        if (Tailport && sym->id == Tailport->id)
          continue;
        if (Headport && sym->id == Headport->id)
          continue;
      }
      if (data->str[sym->id] != sym->defval) {
        if (cnt++ == 0) {
          if (ioput(g, ofile, "\t[") == EOF) {
            return EOF;
          }
          info->level++;
        } else {
          if (ioput(g, ofile, ",\n") == EOF || indent(g, ofile, *info) == EOF) {
            return EOF;
          }
        }
        if (write_canonstr(g, ofile, sym->name, true) == EOF ||
            ioput(g, ofile, "=") == EOF ||
            write_canonstr(g, ofile, data->str[sym->id], true) == EOF) {
          return EOF;
        }
      }
    }
  if (cnt > 0) {
    if (ioput(g, ofile, "]") == EOF) {
      return EOF;
    }
    info->level--;
  }
  AGATTRWF(obj) = true;
  return 0;
}
 
static int write_nodename(Agnode_t *n, iochan_t *ofile) {
  char *name;
  Agraph_t *g;
 
  name = agnameof(n);
  g = agraphof(n);
  if (name) {
    if (write_canonstr(g, ofile, name, false) == EOF) {
      return EOF;
    }
  } else {
    char buf[sizeof("__SUSPECT") + 20];
    snprintf(buf, sizeof(buf), "_%" PRIu64 "_SUSPECT",
             AGID(n)); /* could be deadly wrong */
    if (ioput(g, ofile, buf) == EOF) {
      return EOF;
    }
  }
  return 0;
}
 
static int attrs_written(void *obj) { return AGATTRWF(obj); }
 
static int write_node(Agraph_t *subg, Agnode_t *n, iochan_t *ofile, Dict_t *d,
                      info_t *info) {
  Agraph_t *g;
 
  g = agraphof(n);
  if (indent(g, ofile, *info) == EOF || write_nodename(n, ofile) == EOF) {
    return EOF;
  }
  if (!attrs_written(n)) {
    if (write_nondefault_attrs(n, ofile, d, info) == EOF) {
      return EOF;
    }
  }
  info->node_last_written[AGSEQ(n)] = info->preorder_number[AGSEQ(subg)];
  return ioput(g, ofile, ";\n");
}
 
/* node must be written if it wasn't already emitted because of
 * a subgraph or one of its predecessors, and if it is a singleton
 * or has non-default attributes.
 */
static bool write_node_test(Agraph_t *g, Agnode_t *n, info_t *info) {
  /* test if node was already written in g or a subgraph of g */
  if (info->node_last_written[AGSEQ(n)] >= info->preorder_number[AGSEQ(g)])
    return false;
 
  if (has_no_edges(g, n) || not_default_attrs(g, n))
    return true;
  return false;
}
 
static int write_port(Agedge_t *e, iochan_t *ofile, Agsym_t *port) {
  char *val;
  Agraph_t *g;
 
  if (!port)
    return 0;
  g = agraphof(e);
  val = agxget(e, port);
  if (val[0] == '\0')
    return 0;
 
  if (ioput(g, ofile, ":") == EOF) {
    return EOF;
  }
  if (aghtmlstr(val)) {
    if (write_canonstr(g, ofile, val, true) == EOF) {
      return EOF;
    }
  } else {
    char *s = strchr(val, ':');
    if (s) {
      *s = '\0';
      if (write_canonstr_(g, ofile, val, false) == EOF ||
          ioput(g, ofile, ":") == EOF ||
          write_canonstr_(g, ofile, s + 1, false) == EOF) {
        return EOF;
      }
      *s = ':';
    } else {
      if (write_canonstr_(g, ofile, val, false) == EOF) {
        return EOF;
      }
    }
  }
  return 0;
}
 
static int write_edge(Agedge_t *e, iochan_t *ofile, Dict_t *d, info_t *info) {
  Agnode_t *t, *h;
  Agraph_t *g;
 
  t = AGTAIL(e);
  h = AGHEAD(e);
  g = agraphof(t);
  if (indent(g, ofile, *info) == EOF || write_nodename(t, ofile) == EOF ||
      write_port(e, ofile, Tailport) == EOF ||
      ioput(g, ofile, (agisdirected(agraphof(t)) ? " -> " : " -- ")) == EOF ||
      write_nodename(h, ofile) == EOF ||
      write_port(e, ofile, Headport) == EOF) {
    return EOF;
  }
  if (!attrs_written(e)) {
    if (write_nondefault_attrs(e, ofile, d, info) == EOF) {
      return EOF;
    }
  } else {
    if (write_edge_name(e, ofile, true, info) == EOF) {
      return EOF;
    }
  }
  return ioput(g, ofile, ";\n");
}
 
static int write_edges(iochan_t *ofile, Dict_t *d, info_t *info) {
  for (size_t i = 0; i < info->n_edges; ++i) {
    if (info->edge[i] == NULL || info->edge[i] == EDGE_DONE) {
      continue;
    }
    if (write_edge(info->edge[i], ofile, d, info) == EOF) {
      return EOF;
    }
    info->edge[i] = EDGE_DONE;
  }
  return 0;
}
 
static int write_body(Agraph_t *g, iochan_t *ofile, info_t *info) {
  Agnode_t *n, *prev;
  Agedge_t *e;
  Agdatadict_t *dd;
 
  if (write_subgs(g, ofile, info) == EOF) {
    return EOF;
  }
  dd = agdatadict(g, false);
  for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
    if (write_node_test(g, n, info)) {
      if (write_node(g, n, ofile, dd ? dd->dict.n : 0, info) == EOF) {
        return EOF;
      }
    }
    prev = n;
    for (e = agfstout(g, n); e; e = agnxtout(g, e)) {
      if (prev != aghead(e) && write_node_test(g, aghead(e), info)) {
        if (write_node(g, aghead(e), ofile, dd ? dd->dict.n : 0, info) == EOF) {
          return EOF;
        }
        prev = aghead(e);
      }
      // pend this edge to be emitted later
      if (info->edge[AGSEQ(e)] != EDGE_DONE) {
        info->edge[AGSEQ(e)] = e;
      }
    }
  }
  // flush pending edges to the output file
  if (write_edges(ofile, dd ? dd->dict.e : NULL, info) == EOF) {
    return EOF;
  }
  return 0;
}
 
static void set_attrwf(Agraph_t *g, bool toplevel, bool value) {
  Agraph_t *subg;
  Agnode_t *n;
  Agedge_t *e;
 
  AGATTRWF(g) = value;
  for (subg = agfstsubg(g); subg; subg = agnxtsubg(subg)) {
    set_attrwf(subg, false, value);
  }
  if (toplevel) {
    for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
      AGATTRWF(n) = value;
      for (e = agfstout(g, n); e; e = agnxtout(g, e))
        AGATTRWF(e) = value;
    }
  }
}
 
int agwrite(Agraph_t *g, void *ofile) {
  char *s;
  s = agget(g, "linelength");
  if (s != NULL && gv_isdigit(*s)) {
    unsigned long len = strtoul(s, NULL, 10);
    if ((len == 0 || len >= MIN_OUTPUTLINE) && len <= INT_MAX)
      Max_outputline = (int)len;
  }
  info_t info = before_write(g);
  if (write_hdr(g, ofile, true, &info) == EOF) {
    after_write(info);
    return EOF;
  }
  if (write_body(g, ofile, &info) == EOF) {
    after_write(info);
    return EOF;
  }
  if (write_trl(g, ofile, &info) == EOF) {
    after_write(info);
    return EOF;
  }
  after_write(info);
  Max_outputline = MAX_OUTPUTLINE;
  return AGDISC(g, io)->flush(ofile);
}
 
static uint64_t subgdfs(Agraph_t *g, uint64_t ix, info_t *info) {
  uint64_t ix0 = ix;
  Agraph_t *subg;
 
  info->preorder_number[AGSEQ(g)] = ix0;
  for (subg = agfstsubg(g); subg; subg = agnxtsubg(subg)) {
    ix0 = subgdfs(subg, ix0, info);
  }
  return ix0 + 1;
}
 
static info_t before_write(Agraph_t *g) {
  info_t info = {0};
  set_attrwf(g, true, false);
 
  info.preorder_number = gv_calloc(g->clos->seq[AGRAPH] + 1, sizeof(uint64_t));
  info.node_last_written =
      gv_calloc(g->clos->seq[AGNODE] + 1, sizeof(uint64_t));
  info.edge = gv_calloc(g->clos->seq[AGEDGE] + 1, sizeof(info.edge[0]));
  info.n_edges = g->clos->seq[AGEDGE] + 1;
  subgdfs(g, 1, &info);
  return info;
}
 
static void after_write(info_t info) {
  free(info.preorder_number);
  free(info.node_last_written);
  free(info.edge);
}