gxl2gv.c

Go to the documentation of this file.

 
/*************************************************************************
 * 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    "convert.h"
#include    <cgraph/agxbuf.h>
#include    <cgraph/alloc.h>
#include    <cgraph/exit.h>
#include    <cgraph/gv_ctype.h>
#include    <cgraph/stack.h>
#include    <cgraph/startswith.h>
#include    <cgraph/unreachable.h>
#include    <stdbool.h>
#include    <stdio.h>
#ifdef HAVE_EXPAT
#include    <expat.h>
#include    <limits.h>
#include    <stdlib.h>
 
#ifndef XML_STATUS_ERROR
#define XML_STATUS_ERROR 0
#endif
 
#define NAMEBUF         100
 
#define GXL_ATTR        "_gxl_"
#define GXL_ID      "_gxl_id"
#define GXL_ROLE        "_gxl_role"
#define GXL_HYPER       "_gxl_hypergraph"
#define GXL_FROM    "_gxl_fromorder"
#define GXL_TO      "_gxl_toorder"
#define GXL_TYPE    "_gxl_type"
#define GXL_COMP    "_gxl_composite_"
#define GXL_LOC     "_gxl_locator_"
 
typedef enum {
  TAG_NONE,
  TAG_GRAPH,
  TAG_NODE,
  TAG_EDGE,
  TAG_HTML_LIKE_STRING,
} attr_t;
 
typedef struct {
    agxbuf xml_attr_name;
    agxbuf xml_attr_value;
    agxbuf composite_buffer;
    bool listen;
    attr_t closedElementType;
    attr_t globalAttrType;
    bool compositeReadState;
    bool edgeinverted;
    Dt_t *nameMap;
} userdata_t;
 
static Agraph_t *root;          /* root graph */
static attr_t Current_class;    /* Current element type */
static Agraph_t *G;             /* Current graph */
static Agnode_t *N;             /* Set if Current_class == TAG_NODE */
static Agedge_t *E;             /* Set if Current_class == TAG_EDGE */
 
static gv_stack_t Gstack;
 
typedef struct {
    Dtlink_t link;
    char *name;
    char *unique_name;
} namev_t;
 
static namev_t *make_nitem(namev_t *objp, Dtdisc_t *disc){
    (void)disc;
 
    namev_t *np = malloc(sizeof(namev_t));
    if (np == NULL)
        return NULL;
    np->name = objp->name;
    np->unique_name = 0;
    return np;
}
 
static void free_nitem(void *name) {
    namev_t *np = name;
    free(np->unique_name);
    free(np);
}
 
static Dtdisc_t nameDisc = {
    .key = offsetof(namev_t, name),
    .size = -1,
    .link = offsetof(namev_t, link),
    .makef = (Dtmake_f)make_nitem,
    .freef = free_nitem,
};
 
static userdata_t genUserdata(void) {
  userdata_t user = {0};
  user.listen = false;
  user.closedElementType = TAG_NONE;
  user.globalAttrType = TAG_NONE;
  user.compositeReadState = false;
  user.edgeinverted = false;
  user.nameMap = dtopen(&nameDisc, Dtoset);
  return user;
}
 
static void freeUserdata(userdata_t ud) {
  dtclose(ud.nameMap);
  agxbfree(&ud.xml_attr_name);
  agxbfree(&ud.xml_attr_value);
  agxbfree(&ud.composite_buffer);
}
 
static void addToMap(Dt_t * map, char *name, char *uniqueName)
{
    namev_t obj;
    namev_t *objp;
 
    obj.name = name;
    objp = dtinsert(map, &obj);
    assert(objp->unique_name == 0);
    objp->unique_name = gv_strdup(uniqueName);
}
 
static char *mapLookup(Dt_t *nm, const char *name) {
    namev_t *objp = dtmatch(nm, name);
    if (objp)
        return objp->unique_name;
    else
        return 0;
}
 
static int isAnonGraph(const char *name)
{
    if (*name++ != '%')
        return 0;
    while (gv_isdigit(*name))
        name++;                 /* skip over digits */
    return (*name == '\0');
}
 
static void push_subg(Agraph_t * g)
{
  // insert the new graph
  stack_push(&Gstack, g);
 
  // save the root if this is the first graph
  if (stack_size(&Gstack) == 1) {
    root = g;
  }
 
  // update the top graph
  G = g;
}
 
static Agraph_t *pop_subg(void)
{
  // is the stack empty?
  if (stack_is_empty(&Gstack)) {
    fprintf(stderr, "gxl2gv: Gstack underflow in graph parser\n");
    graphviz_exit(EXIT_FAILURE);
  }
 
  // pop the top graph
  Agraph_t *g = stack_pop(&Gstack);
 
  // update the top graph
  if (!stack_is_empty(&Gstack))
    G = stack_top(&Gstack);
 
  return g;
}
 
static Agnode_t *bind_node(const char *name)
{
    N = agnode(G, (char *) name, 1);
    return N;
}
 
static Agedge_t *bind_edge(const char *tail, const char *head)
{
    Agnode_t *tailNode, *headNode;
    char *key = 0;
 
    tailNode = agnode(G, (char *) tail, 1);
    headNode = agnode(G, (char *) head, 1);
    E = agedge(G, tailNode, headNode, key, 1);
    return E;
}
 
static int get_xml_attr(char *attrname, const char **atts)
{
    int count = 0;
    while (atts[count] != NULL) {
        if (strcmp(attrname, atts[count]) == 0) {
            return count + 1;
        }
        count += 2;
    }
    return -1;
}
 
static void setName(Dt_t * names, Agobj_t * n, char *value)
{
    Agsym_t *ap;
    char *oldName;
 
    ap = agattr(root, AGTYPE(n), GXL_ID, "");
    agxset(n, ap, agnameof(n));
    oldName = agxget(n, ap);    /* set/get gives us new copy */
    addToMap(names, oldName, value);
    agrename(n, value);
}
 
static char *defval = "";
 
static void
setNodeAttr(Agnode_t * np, char *name, char *value, userdata_t * ud,
  bool is_html)
{
    Agsym_t *ap;
 
    if (strcmp(name, "name") == 0) {
        setName(ud->nameMap, (Agobj_t *) np, value);
    } else {
        ap = agattr(root, AGNODE, name, 0);
        if (!ap)
            ap = agattr(root, AGNODE, name, defval);
        if (is_html) {
            char *val = agstrdup_html(root, value);
            agxset(np, ap, val);
            agstrfree(root, val); // drop the extra reference count we bumped for val
        } else {
            agxset(np, ap, value);
        }
    }
}
 
#define NODELBL "node:"
#define NLBLLEN (sizeof(NODELBL)-1)
#define EDGELBL "edge:"
#define ELBLLEN (sizeof(EDGELBL)-1)
 
/* setGlobalNodeAttr:
 * Set global node attribute.
 * The names must always begin with "node:".
 */
static void
setGlobalNodeAttr(Agraph_t * g, char *name, char *value)
{
    if (!startswith(name, NODELBL))
        fprintf(stderr,
                "Warning: global node attribute %s in graph %s does not begin with the prefix %s\n",
                name, agnameof(g), NODELBL);
    else
        name += NLBLLEN;
    if ((g != root) && !agattr(root, AGNODE, name, 0))
        agattr(root, AGNODE, name, defval);
    agattr(G, AGNODE, name, value);
}
 
static void
setEdgeAttr(Agedge_t * ep, char *name, char *value, userdata_t * ud,
  bool is_html)
{
    Agsym_t *ap;
    char *attrname;
 
    if (strcmp(name, "headport") == 0) {
        if (ud->edgeinverted)
            attrname = "tailport";
        else
            attrname = "headport";
        ap = agattr(root, AGEDGE, attrname, 0);
        if (!ap)
            ap = agattr(root, AGEDGE, attrname, defval);
    } else if (strcmp(name, "tailport") == 0) {
        if (ud->edgeinverted)
            attrname = "headport";
        else
            attrname = "tailport";
        ap = agattr(root, AGEDGE, attrname, 0);
        if (!ap)
            ap = agattr(root, AGEDGE, attrname, defval);
    } else {
        ap = agattr(root, AGEDGE, name, 0);
        if (!ap)
            ap = agattr(root, AGEDGE, name, defval);
    }
 
    if (is_html) {
        char *val = agstrdup_html(root, value);
        agxset(ep, ap, val);
        agstrfree(root, val); // drop the extra reference count we bumped for val
    } else {
        agxset(ep, ap, value);
    }
}
 
/* setGlobalEdgeAttr:
 * Set global edge attribute.
 * The names always begin with "edge:".
 */
static void
setGlobalEdgeAttr(Agraph_t * g, char *name, char *value)
{
    if (!startswith(name, EDGELBL))
        fprintf(stderr,
                "Warning: global edge attribute %s in graph %s does not begin with the prefix %s\n",
                name, agnameof(g), EDGELBL);
    else
        name += ELBLLEN;
    if ((g != root) && !agattr(root, AGEDGE, name, 0))
        agattr(root, AGEDGE, name, defval);
    agattr(g, AGEDGE, name, value);
}
 
static void
setGraphAttr(Agraph_t * g, char *name, char *value, userdata_t * ud)
{
    Agsym_t *ap;
 
    if ((g == root) && !strcmp(name, "strict") && !strcmp(value, "true")) {
        g->desc.strict = true;
    } else if (strcmp(name, "name") == 0)
        setName(ud->nameMap, (Agobj_t *) g, value);
    else {
        ap = agattr(root, AGRAPH, name, 0);
        if (ap)
            agxset(g, ap, value);
        else if (g == root)
            agattr(root, AGRAPH, name, value);
        else {
            ap = agattr(root, AGRAPH, name, defval);
            agxset(g, ap, value);
        }
    }
}
 
static void setAttr(char *name, char *value, userdata_t * ud, bool is_html)
{
    switch (Current_class) {
    case TAG_GRAPH:
        setGraphAttr(G, name, value, ud);
        break;
    case TAG_NODE:
        setNodeAttr(N, name, value, ud, is_html);
        break;
    case TAG_EDGE:
        setEdgeAttr(E, name, value, ud, is_html);
        break;
    default:
        break;
    }
}
 
/*------------- expat handlers ----------------------------------*/
 
static void
startElementHandler(void *userData, const char *name, const char **atts)
{
    int pos;
    userdata_t *ud = userData;
    Agraph_t *g = NULL;
 
    if (strcmp(name, "gxl") == 0) {
        /* do nothing */
    } else if (strcmp(name, "graph") == 0) {
        const char *edgeMode = "";
        char buf[NAMEBUF];      /* holds % + number */
 
        Current_class = TAG_GRAPH;
        if (ud->closedElementType == TAG_GRAPH) {
            fprintf(stderr,
                    "Warning: Node contains more than one graph.\n");
        }
        pos = get_xml_attr("id", atts);
        if (pos <= 0) {
            fprintf(stderr, "Error: Graph has no ID attribute.\n");
            graphviz_exit(EXIT_FAILURE);
        }
        const char *id = atts[pos];
        pos = get_xml_attr("edgemode", atts);
        if (pos > 0) {
            edgeMode = atts[pos];
        }
 
        if (stack_is_empty(&Gstack)) {
            if (strcmp(edgeMode, "directed") == 0) {
                g = agopen((char *) id, Agdirected, &AgDefaultDisc);
            } else if (strcmp(edgeMode, "undirected") == 0) {
                g = agopen((char *) id, Agundirected, &AgDefaultDisc);
            } else {
                fprintf(stderr,
                        "Warning: graph has no edgemode attribute");
                fprintf(stderr, " - assume directed\n");
                g = agopen((char *) id, Agdirected, &AgDefaultDisc);
            }
            push_subg(g);
        } else {
            Agraph_t *subg;
            if (isAnonGraph(id)) {
                static int anon_id = 1;
                snprintf(buf, sizeof(buf), "%%%d", anon_id++);
                id = buf;
            }
            subg = agsubg(G, (char *) id, 1);
            push_subg(subg);
        }
 
        pos = get_xml_attr("role", atts);
        if (pos > 0) {
            setGraphAttr(G, GXL_ROLE, (char *) atts[pos], ud);
        }
 
        pos = get_xml_attr("hypergraph", atts);
        if (pos > 0) {
            setGraphAttr(G, GXL_HYPER, (char *) atts[pos], ud);
        }
 
    } else if (strcmp(name, "node") == 0) {
        Current_class = TAG_NODE;
        pos = get_xml_attr("id", atts);
        if (pos > 0) {
            const char *attrname;
            attrname = atts[pos];
 
            if (attrname != NULL && strcmp(attrname, "") != 0) {
                bind_node(attrname);
            }
        }
 
    } else if (strcmp(name, "edge") == 0) {
        const char *head = "", *tail = "";
        char *tname;
        Agnode_t *t;
 
        Current_class = TAG_EDGE;
        pos = get_xml_attr("from", atts);
        if (pos > 0)
            tail = atts[pos];
        pos = get_xml_attr("to", atts);
        if (pos > 0)
            head = atts[pos];
 
        tname = mapLookup(ud->nameMap, tail);
        if (tname)
            tail = tname;
 
        tname = mapLookup(ud->nameMap, head);
        if (tname)
            head = tname;
 
        bind_edge(tail, head);
 
        t = AGTAIL(E);
        tname = agnameof(t);
 
        if (strcmp(tname, tail) == 0) {
            ud->edgeinverted = false;
        } else if (strcmp(tname, head) == 0) {
            ud->edgeinverted = true;
        }
 
        pos = get_xml_attr("fromorder", atts);
        if (pos > 0) {
            setEdgeAttr(E, GXL_FROM, (char *) atts[pos], ud, false);
        }
 
        pos = get_xml_attr("toorder", atts);
        if (pos > 0) {
            setEdgeAttr(E, GXL_TO, (char *) atts[pos], ud, false);
        }
 
        pos = get_xml_attr("id", atts);
        if (pos > 0) {
            setEdgeAttr(E, GXL_ID, (char *) atts[pos], ud, false);
        }
    } else if (strcmp(name, "attr") == 0) {
        const char *attrname = atts[get_xml_attr("name", atts)];
 
        agxbput(&ud->xml_attr_name, attrname);
        pos = get_xml_attr("kind", atts);
 
        if (pos > 0) {
            if (strcmp("node", atts[pos]) == 0)
                ud->globalAttrType = TAG_NODE;
            else if (strcmp("edge", atts[pos]) == 0)
                ud->globalAttrType = TAG_EDGE;
            else if (strcmp("graph", atts[pos]) == 0)
                ud->globalAttrType = TAG_GRAPH;
            else if (strcmp("HTML-like string", atts[pos]) == 0)
                ud->globalAttrType = TAG_HTML_LIKE_STRING;
        } else {
            ud->globalAttrType = TAG_NONE;
        }
 
    } else if (strcmp(name, "string") == 0
               || strcmp(name, "bool") == 0
               || strcmp(name, "int") == 0 || strcmp(name, "float") == 0) {
 
        ud->listen = true;
        if (ud->compositeReadState) {
            agxbprint(&ud->composite_buffer, "<%s>", name);
        }
    } else if (strcmp(name, "rel") == 0 || strcmp(name, "relend") == 0) {
        fprintf(stderr, "%s element is ignored by DOT\n", name);
    } else if (strcmp(name, "type") == 0) {
        pos = get_xml_attr("xlink:href", atts);
        if (pos > 0) {
            setAttr(GXL_TYPE, (char *) atts[pos], ud, false);
        }
    } else if (strcmp(name, "locator") == 0) {
        pos = get_xml_attr("xlink:href", atts);
        if (pos > 0) {
            const char *href = atts[pos];
            agxbprint(&ud->xml_attr_value, "%s%s", GXL_LOC, href);
        }
    } else if (strcmp(name, "seq") == 0
               || strcmp(name, "set") == 0
               || strcmp(name, "bag") == 0
               || strcmp(name, "tup") == 0 || strcmp(name, "enum") == 0) {
 
        ud->compositeReadState = true;
        agxbprint(&ud->composite_buffer, "<%s>", name);
    } else {
        /* must be some extension */
        fprintf(stderr,
                "Unknown node %s; DOT does not support extensions.\n",
                name);
    }
}
 
static void endElementHandler(void *userData, const char *name)
{
    userdata_t *ud = userData;
 
    if (strcmp(name, "graph") == 0) {
        pop_subg();
        ud->closedElementType = TAG_GRAPH;
    } else if (strcmp(name, "node") == 0) {
        Current_class = TAG_GRAPH;
        N = 0;
        ud->closedElementType = TAG_NODE;
    } else if (strcmp(name, "edge") == 0) {
        Current_class = TAG_GRAPH;
        E = 0;
        ud->closedElementType = TAG_EDGE;
        ud->edgeinverted = false;
    } else if (strcmp(name, "attr") == 0) {
        agxbuf new_name = {0};
        char *value;
 
        ud->closedElementType = TAG_NONE;
        if (ud->compositeReadState) {
            agxbprint(&new_name, "%s%s", GXL_COMP, agxbuse(&ud->xml_attr_name));
            value = agxbuse(&ud->composite_buffer);
            agxbclear(&ud->xml_attr_value);
            ud->compositeReadState = false;
        } else {
            agxbput(&new_name, agxbuse(&ud->xml_attr_name));
            value = agxbuse(&ud->xml_attr_value);
        }
 
        switch (ud->globalAttrType) {
        case TAG_NONE:
            setAttr(agxbuse(&new_name), value, ud, false);
            break;
        case TAG_NODE:
            setGlobalNodeAttr(G, agxbuse(&new_name), value);
            break;
        case TAG_EDGE:
            setGlobalEdgeAttr(G, agxbuse(&new_name), value);
            break;
        case TAG_GRAPH:
            setGraphAttr(G, agxbuse(&new_name), value, ud);
            break;
        case TAG_HTML_LIKE_STRING:
            setAttr(agxbuse(&new_name), value, ud, true);
            break;
        default:
            UNREACHABLE();
        }
        agxbfree(&new_name);
        ud->globalAttrType = TAG_NONE;
    } else if (strcmp(name, "string") == 0
               || strcmp(name, "bool") == 0
               || strcmp(name, "int") == 0 || strcmp(name, "float") == 0) {
        ud->listen = false;
        if (ud->compositeReadState) {
            agxbprint(&ud->composite_buffer, "</%s>", name);
        }
    } else if (strcmp(name, "seq") == 0
               || strcmp(name, "set") == 0
               || strcmp(name, "bag") == 0
               || strcmp(name, "tup") == 0 || strcmp(name, "enum") == 0) {
        agxbprint(&ud->composite_buffer, "</%s>", name);
    }
}
 
static void characterDataHandler(void *userData, const char *s, int length)
{
    userdata_t *ud = userData;
 
    assert(length >= 0 && "Expat returned negative length data");
    size_t len = (size_t)length;
 
    if (!ud->listen)
        return;
 
    if (ud->compositeReadState) {
        agxbput_n(&ud->composite_buffer, s, len);
        return;
    }
 
    agxbput_n(&ud->xml_attr_value, s, len);
}
 
Agraph_t *gxl_to_gv(FILE * gxlFile)
{
    char buf[BUFSIZ];
    int done;
    userdata_t udata = genUserdata();
    XML_Parser parser = XML_ParserCreate(NULL);
 
    XML_SetUserData(parser, &udata);
    XML_SetElementHandler(parser, startElementHandler, endElementHandler);
    XML_SetCharacterDataHandler(parser, characterDataHandler);
 
    Current_class = TAG_GRAPH;
    root = 0;
    do {
        size_t len = fread(buf, 1, sizeof(buf), gxlFile);
        if (len == 0)
            break;
        done = len < sizeof(buf);
        assert(len <= (size_t)INT_MAX && "too large data for Expat API");
        if (XML_Parse(parser, buf, (int)len, done) == XML_STATUS_ERROR) {
            fprintf(stderr,
                    "%s at line %lu\n",
                    XML_ErrorString(XML_GetErrorCode(parser)),
                    XML_GetCurrentLineNumber(parser));
            graphviz_exit(1);
        }
    } while (!done);
    XML_ParserFree(parser);
    freeUserdata(udata);
    stack_reset(&Gstack);
 
    return root;
}
 
#endif