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 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 <assert.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>              /* need sprintf() */
#include <stdlib.h>
#include <ctype.h>
#include <cgraph/agstrcanon.h>
#include <cgraph/cghdr.h>
#include <inttypes.h>
#include <util/gv_ctype.h>
#include <util/strcasecmp.h>
 
#define EMPTY(s)                (((s) == 0) || (s)[0] == '\0')
#define MAX(a,b)     ((a)>(b)?(a):(b))
#define CHKRV(v)     {if ((v) == EOF) return EOF;}
 
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 Level;
static int Max_outputline = MAX_OUTPUTLINE;
static Agsym_t *Tailport, *Headport;
 
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
        uint64_t *edge_last_written;    // postorder number of subg when edge was last written
} write_info_t;
 
static int write_body(Agraph_t *g, iochan_t *ofile, write_info_t *wr_info);
 
static write_info_t before_write(Agraph_t *);
static void after_write(write_info_t);
 
static int indent(Agraph_t * g, iochan_t * ofile)
{
    int i;
    for (i = Level; i > 0; i--)
        CHKRV(ioput(g, ofile, "\t"));
    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 char *getoutputbuffer(const char *str)
{
    static char *rv;
    static size_t len = 0;
    const size_t req = MAX(agstrcanon_bytes(str), BUFSIZ);
    if (req > len) {
        char *r = realloc(rv, req);
        if (r == NULL)
            return NULL;
        rv = r;
        len = req;
    }
    return rv;
}
 
char *agcanonStr(char *str)
{
    char *buffer = getoutputbuffer(str);
    if (buffer == NULL)
        return NULL;
    return agstrcanon(str, buffer);
}
 
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) {
    int cnt = 0;
    Dict_t *view;
    Agsym_t *sym, *psym;
 
    if (!top)
        view = dtview(dict, NULL);
    else
        view = 0;
    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) {
            CHKRV(indent(g, ofile));
            CHKRV(ioput(g, ofile, name));
            CHKRV(ioput(g, ofile, " ["));
            Level++;
        } else {
            CHKRV(ioput(g, ofile, ",\n"));
            CHKRV(indent(g, ofile));
        }
        CHKRV(write_canonstr(g, ofile, sym->name, true));
        CHKRV(ioput(g, ofile, "="));
        CHKRV(write_canonstr(g, ofile, sym->defval, true));
    }
    if (cnt > 0) {
        Level--;
        if (cnt > 1) {
            CHKRV(ioput(g, ofile, "\n"));
            CHKRV(indent(g, ofile));
        }
        CHKRV(ioput(g, ofile, "];\n"));
    }
    if (!top)
        dtview(dict, view);     /* restore previous view */
    return 0;
}
 
static int write_dicts(Agraph_t *g, iochan_t *ofile, bool top) {
    Agdatadict_t *def;
    if ((def = agdatadict(g, false))) {
        CHKRV(write_dict(g, ofile, "graph", def->dict.g, top));
        CHKRV(write_dict(g, ofile, "node", def->dict.n, top));
        CHKRV(write_dict(g, ofile, "edge", def->dict.e, top));
    }
    return 0;
}
 
static int write_hdr(Agraph_t *g, iochan_t *ofile, bool top) {
    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;
    }
    CHKRV(indent(g, ofile));
    CHKRV(ioput(g, ofile, strict));
 
    /* output "<kind>graph" only for root graphs or graphs with names */
    if (root || hasName) {
        CHKRV(ioput(g, ofile, kind));
        CHKRV(ioput(g, ofile, "graph "));
    }
    if (hasName)
        CHKRV(write_canonstr(g, ofile, name, false));
    CHKRV(ioput(g, ofile, sep));
    CHKRV(ioput(g, ofile, "{\n"));
    Level++;
    CHKRV(write_dicts(g, ofile, top));
    AGATTRWF(g) = true;
    return 0;
}
 
static int write_trl(Agraph_t * g, iochan_t * ofile)
{
    (void)g;
    Level--;
    CHKRV(indent(g, ofile));
    CHKRV(ioput(g, ofile, "}\n"));
    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, write_info_t *wr_info) {
    Agraph_t *subg;
 
    for (subg = agfstsubg(g); subg; subg = agnxtsubg(subg)) {
        if (irrelevant_subgraph(subg)) {
            write_subgs(subg, ofile, wr_info);
        }
        else {
            CHKRV(write_hdr(subg, ofile, false));
            CHKRV(write_body(subg, ofile, wr_info));
            CHKRV(write_trl(subg, ofile));
        }
    }
    return 0;
}
 
static int write_edge_name(Agedge_t *e, iochan_t *ofile, bool terminate) {
    char *p;
    Agraph_t *g;
 
    p = agnameof(e);
    g = agraphof(e);
    if (!EMPTY(p)) {
        if (!terminate) {
            Level++;
        }
        CHKRV(ioput(g, ofile, "\t[key="));
        CHKRV(write_canonstr(g, ofile, p, false));
        if (terminate)
            CHKRV(ioput(g, ofile, "]"));
        return 1;
    }
    return 0;
}
 
 
static int write_nondefault_attrs(void *obj, iochan_t * ofile,
                                  Dict_t * defdict)
{
    Agattr_t *data;
    Agsym_t *sym;
    Agraph_t *g;
    int cnt = 0;
    int rv;
 
    if (AGTYPE(obj) == AGINEDGE || AGTYPE(obj) == AGOUTEDGE) {
        CHKRV(rv = write_edge_name(obj, ofile, false));
        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) {
                    CHKRV(ioput(g, ofile, "\t["));
                    Level++;
                } else {
                    CHKRV(ioput(g, ofile, ",\n"));
                    CHKRV(indent(g, ofile));
                }
                CHKRV(write_canonstr(g, ofile, sym->name, true));
                CHKRV(ioput(g, ofile, "="));
                CHKRV(write_canonstr(g, ofile, data->str[sym->id], true));
            }
        }
    if (cnt > 0) {
        CHKRV(ioput(g, ofile, "]"));
        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) {
        CHKRV(write_canonstr(g, ofile, name, false));
    } else {
        char buf[sizeof("__SUSPECT") + 20];
        snprintf(buf, sizeof(buf), "_%" PRIu64 "_SUSPECT", AGID(n));    /* could be deadly wrong */
        CHKRV(ioput(g, ofile, buf));
    }
    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,
                      write_info_t *wr_info) {
    Agraph_t *g;
 
    g = agraphof(n);
    CHKRV(indent(g, ofile));
    CHKRV(write_nodename(n, ofile));
    if (!attrs_written(n))
        CHKRV(write_nondefault_attrs(n, ofile, d));
    wr_info->node_last_written[AGSEQ(n)] =
        wr_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, write_info_t *wr_info) {
    /* test if node was already written in g or a subgraph of g */
    if (wr_info->node_last_written[AGSEQ(n)] >=
        wr_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;
 
    CHKRV(ioput(g, ofile, ":"));
    if (aghtmlstr(val)) {
        CHKRV(write_canonstr(g, ofile, val, true));
    } else {
        char *s = strchr(val, ':');
        if (s) {
            *s = '\0';
            CHKRV(_write_canonstr(g, ofile, val, false));
            CHKRV(ioput(g, ofile, ":"));
            CHKRV(_write_canonstr(g, ofile, s + 1, false));
            *s = ':';
        } else {
            CHKRV(_write_canonstr(g, ofile, val, false));
        }
    }
    return 0;
}
 
static bool write_edge_test(Agraph_t *g, Agedge_t *e, write_info_t *wr_info) {
    if (wr_info->edge_last_written[AGSEQ(e)] >=
        wr_info->preorder_number[AGSEQ(g)]) return false;
    return true;
}
 
static int write_edge(Agraph_t *subg, Agedge_t *e, iochan_t *ofile, Dict_t *d,
                      write_info_t *wr_info) {
    Agnode_t *t, *h;
    Agraph_t *g;
 
    t = AGTAIL(e);
    h = AGHEAD(e);
    g = agraphof(t);
    CHKRV(indent(g, ofile));
    CHKRV(write_nodename(t, ofile));
    CHKRV(write_port(e, ofile, Tailport));
    CHKRV(ioput(g, ofile, (agisdirected(agraphof(t)) ? " -> " : " -- ")));
    CHKRV(write_nodename(h, ofile));
    CHKRV(write_port(e, ofile, Headport));
    if (!attrs_written(e)) {
        CHKRV(write_nondefault_attrs(e, ofile, d));
    } else {
        CHKRV(write_edge_name(e, ofile, true));
    }
    wr_info->edge_last_written[AGSEQ(e)] =
        wr_info->preorder_number[AGSEQ(subg)];
    return ioput(g, ofile, ";\n");
}
 
static int write_body(Agraph_t *g, iochan_t *ofile, write_info_t *wr_info) {
    Agnode_t *n, *prev;
    Agedge_t *e;
    Agdatadict_t *dd;
 
    CHKRV(write_subgs(g, ofile, wr_info));
    dd = agdatadict(g, false);
    for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
        if (write_node_test(g, n, wr_info))
            CHKRV(write_node(g, n, ofile, dd ? dd->dict.n : 0, wr_info));
        prev = n;
        for (e = agfstout(g, n); e; e = agnxtout(g, e)) {
            if (prev != aghead(e) && write_node_test(g, aghead(e), wr_info)) {
                CHKRV(write_node(g, aghead(e), ofile, dd ? dd->dict.n : 0, wr_info));
                prev = aghead(e);
            }
            if (write_edge_test(g, e, wr_info))
                CHKRV(write_edge(g, e, ofile, dd ? dd->dict.e : 0, wr_info));
        }
 
        }
    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;
    Level = 0;                  /* re-initialize tab level */
    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;
    }
    write_info_t wr_info = before_write(g);
    CHKRV(write_hdr(g, ofile, true));
    CHKRV(write_body(g, ofile, &wr_info));
    CHKRV(write_trl(g, ofile));
    after_write(wr_info);
    Max_outputline = MAX_OUTPUTLINE;
    return AGDISC(g, io)->flush(ofile);
}
 
static uint64_t subgdfs(Agraph_t *g, uint64_t ix, write_info_t *wr_info) {
    uint64_t ix0 = ix;
    Agraph_t *subg;
 
    wr_info->preorder_number[AGSEQ(g)] = ix0;
    for (subg = agfstsubg(g); subg; subg = agnxtsubg(subg)) {
        ix0 = subgdfs(subg, ix0, wr_info);
    }
    return ix0 + 1;
}
 
static write_info_t before_write(Agraph_t *g) {
    write_info_t wr_info = {0};
    set_attrwf(g, true, false);
    
    wr_info.preorder_number = gv_calloc(g->clos->seq[AGRAPH] + 1, sizeof(uint64_t));
    wr_info.node_last_written = gv_calloc(g->clos->seq[AGNODE] + 1, sizeof(uint64_t));
    wr_info.edge_last_written = gv_calloc(g->clos->seq[AGEDGE] + 1, sizeof(uint64_t));
    subgdfs(g, 1, &wr_info);
    return wr_info;
}
 
static void after_write(write_info_t wr_info) {
  free(wr_info.preorder_number);
  free(wr_info.node_last_written);
  free(wr_info.edge_last_written);
}