htmlparse.y

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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
 *************************************************************************/
 
%require "3.0"
 
  /* By default, Bison emits a parser using symbols prefixed with "yy". Graphviz
   * contains multiple Bison-generated parsers, so we alter this prefix to avoid
   * symbol clashes.
   */
%define api.prefix {html}
 
%{
 
#include <cgraph/alloc.h>
#include <common/render.h>
#include <common/htmltable.h>
#include <common/htmllex.h>
 
extern int htmlparse(void);
 
typedef struct sfont_t {
    textfont_t *cfont;  
    struct sfont_t *pfont;
} sfont_t;
 
static struct {
  htmllabel_t* lbl;       /* Generated label */
  htmltbl_t*   tblstack;  /* Stack of tables maintained during parsing */
  Dt_t*        fitemList; /* Dictionary for font text items */
  Dt_t*        fspanList; 
  agxbuf*      str;       /* Buffer for text */
  sfont_t*     fontstack;
  GVC_t*       gvc;
} HTMLstate;
 
/* free_ritem:
 * Free row. This closes and frees row's list, then
 * the pitem itself is freed.
 */
static void free_ritem(void *item) {
  pitem *p = item;
  dtclose (p->u.rp);
  free (p);
}
 
/* cleanTbl:
 * Clean up table if error in parsing.
 */
static void
cleanTbl (htmltbl_t* tp)
{
  dtclose (tp->u.p.rows);
  free_html_data (&tp->data);
  free (tp);
}
 
/* cleanCell:
 * Clean up cell if error in parsing.
 */
static void
cleanCell (htmlcell_t* cp)
{
  if (cp->child.kind == HTML_TBL) cleanTbl (cp->child.u.tbl);
  else if (cp->child.kind == HTML_TEXT) free_html_text (cp->child.u.txt);
  free_html_data (&cp->data);
  free (cp);
}
 
/* free_citem:
 * Free cell item during parsing. This frees cell and pitem.
 */
static void free_citem(void *item) {
  pitem *p = item;
  cleanCell (p->u.cp);
  free (p);
}
 
static Dtdisc_t rowDisc = {
    .key = offsetof(pitem, u),
    .size = sizeof(void *),
    .link = offsetof(pitem, link),
    .freef = free_ritem,
};
static Dtdisc_t cellDisc = {
    .key = offsetof(pitem, u),
    .size = sizeof(void *),
    .link = offsetof(pitem, link),
    .freef = free,
};
 
typedef struct {
    Dtlink_t    link;
    textspan_t  ti;
} fitem;
 
typedef struct {
    Dtlink_t     link;
    htextspan_t  lp;
} fspan;
 
static void free_fitem(void *item) {
    fitem *p = item;
    free (p->ti.str);
    free (p);
}
 
static void free_fspan(void *span) {
    fspan *p = span;
    textspan_t* ti;
 
    if (p->lp.nitems) {
        ti = p->lp.items;
        for (size_t i = 0; i < p->lp.nitems; i++) {
            free (ti->str);
            ti++;
        }
        free (p->lp.items);
    }
    free (p);
}
 
static Dtdisc_t fstrDisc = {
    .link = offsetof(fitem, link),
    .freef = free,
};
 
static Dtdisc_t fspanDisc = {
    .link = offsetof(fspan, link),
    .freef = free,
};
 
/* appendFItemList:
 * Append a new fitem to the list.
 */
static void
appendFItemList (agxbuf *ag)
{
    fitem *fi = gv_alloc(sizeof(fitem));
 
    fi->ti.str = agxbdisown(ag);
    fi->ti.font = HTMLstate.fontstack->cfont;
    dtinsert(HTMLstate.fitemList, fi);
}       
 
/* appendFLineList:
 */
static void 
appendFLineList (int v)
{
    fspan *ln = gv_alloc(sizeof(fspan));
    fitem *fi;
    Dt_t *ilist = HTMLstate.fitemList;
 
    size_t cnt = (size_t)dtsize(ilist);
    ln->lp.just = v;
    if (cnt) {
        int i = 0;
        ln->lp.nitems = cnt;
        ln->lp.items = gv_calloc(cnt, sizeof(textspan_t));
 
        fi = (fitem*)dtflatten(ilist);
        for (; fi; fi = (fitem*)dtlink(fitemList, fi)) {
                /* NOTE: When fitemList is closed, it uses free, which only frees the container,
                 * not the contents, so this copy is safe.
                 */
            ln->lp.items[i] = fi->ti;  
            i++;
        }
    }
    else {
        ln->lp.items = gv_alloc(sizeof(textspan_t));
        ln->lp.nitems = 1;
        ln->lp.items[0].str = gv_strdup("");
        ln->lp.items[0].font = HTMLstate.fontstack->cfont;
    }
 
    dtclear(ilist);
 
    dtinsert(HTMLstate.fspanList, ln);
}
 
static htmltxt_t*
mkText(void)
{
    Dt_t * ispan = HTMLstate.fspanList;
    fspan *fl ;
    htmltxt_t *hft = gv_alloc(sizeof(htmltxt_t));
    
    if (dtsize (HTMLstate.fitemList)) 
        appendFLineList (UNSET_ALIGN);
 
    size_t cnt = (size_t)dtsize(ispan);
    hft->nspans = cnt;
        
    if (cnt) {
        int i = 0;
        hft->spans = gv_calloc(cnt, sizeof(htextspan_t));
        for(fl=dtfirst(ispan); fl; fl=dtnext(ispan,fl)) {
            hft->spans[i] = fl->lp;
            i++;
        }
    }
    
    dtclear(ispan);
 
    return hft;
}
 
static pitem* lastRow (void)
{
  htmltbl_t* tbl = HTMLstate.tblstack;
  pitem*     sp = dtlast (tbl->u.p.rows);
  return sp;
}
 
/* addRow:
 * Add new cell row to current table.
 */
static pitem* addRow (void)
{
  Dt_t*      dp = dtopen(&cellDisc, Dtqueue);
  htmltbl_t* tbl = HTMLstate.tblstack;
  pitem*     sp = gv_alloc(sizeof(pitem));
  sp->u.rp = dp;
  if (tbl->hrule)
    sp->ruled = 1;
  dtinsert (tbl->u.p.rows, sp);
  return sp;
}
 
/* setCell:
 * Set cell body and type and attach to row
 */
static void setCell(htmlcell_t *cp, void *obj, char kind) {
  pitem*     sp = gv_alloc(sizeof(pitem));
  htmltbl_t* tbl = HTMLstate.tblstack;
  pitem*     rp = dtlast (tbl->u.p.rows);
  Dt_t*      row = rp->u.rp;
  sp->u.cp = cp;
  dtinsert (row, sp);
  cp->child.kind = kind;
  if (tbl->vrule)
    cp->ruled = HTML_VRULE;
  
  if(kind == HTML_TEXT)
        cp->child.u.txt = obj;
  else if (kind == HTML_IMAGE)
    cp->child.u.img = obj;
  else
    cp->child.u.tbl = obj;
}
 
/* mkLabel:
 * Create label, given body and type.
 */
static htmllabel_t *mkLabel(void *obj, char kind) {
  htmllabel_t* lp = gv_alloc(sizeof(htmllabel_t));
 
  lp->kind = kind;
  if (kind == HTML_TEXT)
    lp->u.txt = obj;
  else
    lp->u.tbl = obj;
  return lp;
}
 
/* freeFontstack:
 * Free all stack items but the last, which is
 * put on artificially during in parseHTML.
 */
static void
freeFontstack(void)
{
    sfont_t* s;
    sfont_t* next;
 
    for (s = HTMLstate.fontstack; (next = s->pfont); s = next) {
        free(s);
    }
}
 
/* cleanup:
 * Called on error. Frees resources allocated during parsing.
 * This includes a label, plus a walk down the stack of
 * tables. Note that we use the free_citem function to actually
 * free cells.
 */
static void cleanup (void)
{
  htmltbl_t* tp = HTMLstate.tblstack;
  htmltbl_t* next;
 
  if (HTMLstate.lbl) {
    free_html_label (HTMLstate.lbl,1);
    HTMLstate.lbl = NULL;
  }
  cellDisc.freef = free_citem;
  while (tp) {
    next = tp->u.p.prev;
    cleanTbl (tp);
    tp = next;
  }
  cellDisc.freef = free;
 
  fstrDisc.freef = free_fitem;
  dtclear (HTMLstate.fitemList);
  fstrDisc.freef = free;
 
  fspanDisc.freef = free_fspan;
  dtclear (HTMLstate.fspanList);
  fspanDisc.freef = free;
 
  freeFontstack();
}
 
/* nonSpace:
 * Return 1 if s contains a non-space character.
 */
static int nonSpace (char* s)
{
  char   c;
 
  while ((c = *s++)) {
    if (c != ' ') return 1;
  }
  return 0;
}
 
/* pushFont:
 * Fonts are allocated in the lexer.
 */
static void
pushFont (textfont_t *fp)
{
    sfont_t *ft = gv_alloc(sizeof(sfont_t));
    textfont_t* curfont = HTMLstate.fontstack->cfont;
    textfont_t  f = *fp;
 
    if (curfont) {
        if (!f.color && curfont->color)
            f.color = curfont->color;
        if ((f.size < 0.0) && (curfont->size >= 0.0))
            f.size = curfont->size;
        if (!f.name && curfont->name)
            f.name = curfont->name;
        if (curfont->flags)
            f.flags |= curfont->flags;
    }
 
    ft->cfont = dtinsert(HTMLstate.gvc->textfont_dt, &f);
    ft->pfont = HTMLstate.fontstack;
    HTMLstate.fontstack = ft;
}
 
/* popFont:
 */
static void 
popFont (void)
{
    sfont_t* curfont = HTMLstate.fontstack;
    sfont_t* prevfont = curfont->pfont;
 
    free (curfont);
    HTMLstate.fontstack = prevfont;
}
 
%}
 
%union  {
  int    i;
  htmltxt_t*  txt;
  htmlcell_t*  cell;
  htmltbl_t*   tbl;
  textfont_t*  font;
  htmlimg_t*   img;
  pitem*       p;
}
 
%token T_end_br T_end_img T_row T_end_row T_html T_end_html
%token T_end_table T_end_cell T_end_font T_string T_error
%token T_n_italic T_n_bold T_n_underline  T_n_overline T_n_sup T_n_sub T_n_s
%token T_HR T_hr T_end_hr
%token T_VR T_vr T_end_vr
%token <i> T_BR T_br
%token <img> T_IMG T_img
%token <tbl> T_table
%token <cell> T_cell
%token <font> T_font T_italic T_bold T_underline T_overline T_sup T_sub T_s
 
%type <txt> fonttext
%type <cell> cell cells
%type <i> br  
%type <tbl> table fonttable
%type <img> image
%type <p> row rows
 
%start html
             
%%
 
html  : T_html fonttext T_end_html { HTMLstate.lbl = mkLabel($2,HTML_TEXT); }
      | T_html fonttable T_end_html { HTMLstate.lbl = mkLabel($2,HTML_TBL); }
      | error { cleanup(); YYABORT; }
      ;
 
fonttext : text { $$ = mkText(); }
      ;
 
text : text textitem  
     | textitem 
     ;
 
textitem : string { appendFItemList(HTMLstate.str);}
         | br {appendFLineList($1);}
         | font text n_font
         | italic text n_italic
         | underline text n_underline
         | overline text n_overline
         | bold text n_bold
         | sup text n_sup
         | sub text n_sub
         | strike text n_strike
         ;
 
font : T_font { pushFont ($1); }
      ;
 
n_font : T_end_font { popFont (); }
      ;
 
italic : T_italic {pushFont($1);}
          ;
 
n_italic : T_n_italic {popFont();}
            ;
 
bold : T_bold {pushFont($1);}
          ;
 
n_bold : T_n_bold {popFont();}
            ;
 
strike : T_s {pushFont($1);}
          ;
 
n_strike : T_n_s {popFont();}
            ;
 
underline : T_underline {pushFont($1);}
          ;
 
n_underline : T_n_underline {popFont();}
            ;
 
overline : T_overline {pushFont($1);}
          ;
 
n_overline : T_n_overline {popFont();}
            ;
 
sup : T_sup {pushFont($1);}
          ;
 
n_sup : T_n_sup {popFont();}
            ;
 
sub : T_sub {pushFont($1);}
          ;
 
n_sub : T_n_sub {popFont();}
            ;
 
br     : T_br T_end_br { $$ = $1; }
       | T_BR { $$ = $1; }
       ;
 
string : T_string
       | string T_string
       ;
 
table : opt_space T_table { 
          if (nonSpace(agxbuse(HTMLstate.str))) {
            htmlerror ("Syntax error: non-space string used before <TABLE>");
            cleanup(); YYABORT;
          }
          $2->u.p.prev = HTMLstate.tblstack;
          $2->u.p.rows = dtopen(&rowDisc, Dtqueue);
          HTMLstate.tblstack = $2;
          $2->font = HTMLstate.fontstack->cfont;
          $<tbl>$ = $2;
        }
        rows T_end_table opt_space {
          if (nonSpace(agxbuse(HTMLstate.str))) {
            htmlerror ("Syntax error: non-space string used after </TABLE>");
            cleanup(); YYABORT;
          }
          $$ = HTMLstate.tblstack;
          HTMLstate.tblstack = HTMLstate.tblstack->u.p.prev;
        }
      ;
 
fonttable : table { $$ = $1; }
          | font table n_font { $$=$2; }
          | italic table n_italic { $$=$2; }
          | underline table n_underline { $$=$2; }
          | overline table n_overline { $$=$2; }
          | bold table n_bold { $$=$2; }
          ;
 
opt_space : string 
          | /* empty*/
          ;
 
rows : row { $$ = $1; }
     | rows row { $$ = $2; }
     | rows HR row { $1->ruled = 1; $$ = $3; }
     ;
 
row : T_row { addRow (); } cells T_end_row { $$ = lastRow(); }
      ;
 
cells : cell { $$ = $1; }
      | cells cell { $$ = $2; }
      | cells VR cell { $1->ruled |= HTML_VRULE; $$ = $3; }
      ;
 
cell : T_cell fonttable { setCell($1,$2,HTML_TBL); } T_end_cell { $$ = $1; }
     | T_cell fonttext { setCell($1,$2,HTML_TEXT); } T_end_cell { $$ = $1; }
     | T_cell image { setCell($1,$2,HTML_IMAGE); } T_end_cell { $$ = $1; }
     | T_cell { setCell($1,mkText(),HTML_TEXT); } T_end_cell { $$ = $1; }
     ;
 
image  : T_img T_end_img { $$ = $1; }
       | T_IMG { $$ = $1; }
       ;
 
HR  : T_hr T_end_hr
    | T_HR
    ;
 
VR  : T_vr T_end_vr
    | T_VR
    ;
 
 
%%
 
/* parseHTML:
 * Return parsed label or NULL if failure.
 * Set warn to 0 on success; 1 for warning message; 2 if no expat; 3 for error
 * message.
 */
htmllabel_t*
parseHTML (char* txt, int* warn, htmlenv_t *env)
{
  agxbuf        str = {0};
  htmllabel_t*  l;
  sfont_t       dfltf;
 
  dfltf.cfont = NULL;
  dfltf.pfont = NULL;
  HTMLstate.fontstack = &dfltf;
  HTMLstate.tblstack = 0;
  HTMLstate.lbl = 0;
  HTMLstate.gvc = GD_gvc(env->g);
  HTMLstate.fitemList = dtopen(&fstrDisc, Dtqueue);
  HTMLstate.fspanList = dtopen(&fspanDisc, Dtqueue);
 
  HTMLstate.str = &str;
  
  if (initHTMLlexer (txt, &str, env)) {/* failed: no libexpat - give up */
    *warn = 2;
    l = NULL;
  }
  else {
    htmlparse();
    *warn = clearHTMLlexer ();
    l = HTMLstate.lbl;
  }
 
  dtclose (HTMLstate.fitemList);
  dtclose (HTMLstate.fspanList);
  
  HTMLstate.fitemList = NULL;
  HTMLstate.fspanList = NULL;
  HTMLstate.fontstack = NULL;
  
  agxbfree (&str);
 
  return l;
}