cadi/core/src/main/java/org/onap/aaf/cadi/wsse/XReader.java

   1 /**
   2  * ============LICENSE_START====================================================
   3  * org.onap.aaf
   4  * ===========================================================================
   5  * Copyright (c) 2018 AT&T Intellectual Property. All rights reserved.
   6  * ===========================================================================
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  * ============LICENSE_END====================================================
  19  *
  20  */
  21
  22 package org.onap.aaf.cadi.wsse;
  23
  24 import java.io.ByteArrayOutputStream;
  25 import java.io.IOException;
  26 import java.io.InputStream;
  27 import java.util.ArrayList;
  28 import java.util.HashMap;
  29 import java.util.List;
  30 import java.util.Map;
  31 import java.util.Stack;
  32
  33 import javax.xml.stream.XMLStreamException;
  34
  35 /**
  36  * XReader
  37  * This class works similarly as StAX, except StAX has more behavior than is needed.  That would be ok, but
  38  * StAX also was Buffering in their code in such as way as to read most if not all the incoming stream into memory,
  39  * defeating the purpose of pre-reading only the Header
  40  *
  41  * This Reader does no back-tracking, but is able to create events based on syntax and given state only, leaving the
  42  * Read-ahead mode of the InputStream up to the other classes.
  43  *
  44  * At this time, we only implement the important events, though if this is good enough, it could be expanded, perhaps to
  45  * replace the original XMLReader from StAX.
  46  *
  47  * @author Jonathan
  48  *
  49  */
  50 // @SuppressWarnings("restriction")
  51 public class XReader {
  52         private XEvent curr,another;
  53         private InputStream is;
  54         private ByteArrayOutputStream baos;
  55         private int state, count, last;
  56
  57         private Stack<Map<String,String>> nsses;
  58
  59         public XReader(InputStream is) {
  60                 this.is = is;
  61                 curr = another = null;
  62                 baos = new ByteArrayOutputStream();
  63                 state = BEGIN_DOC;
  64                 count = 0;
  65                 nsses = new Stack<Map<String,String>>();
  66         }
  67
  68         public boolean hasNext() throws XMLStreamException {
  69                 if(curr==null) {
  70                         curr = parse();
  71                 }
  72                 return curr!=null;
  73         }
  74
  75         public XEvent nextEvent() {
  76                 XEvent xe = curr;
  77                 curr = null;
  78                 return xe;
  79         }
  80
  81         //
  82         // State Flags
  83         //
  84         // Note: The State of parsing XML can be complicated.  There are too many to cleanly keep in "booleans".  Additionally,
  85         // there are certain checks that can be better made with Bitwise operations within switches
  86         // Keeping track of state this way also helps us to accomplish logic without storing any back characters except one
  87         private final static int BEGIN_DOC=  0x000001;
  88         private final static int DOC_TYPE=   0x000002;
  89         private final static int QUESTION_F= 0x000004;
  90         private final static int QUESTION =  0x000008;
  91         private final static int START_TAG = 0x000010;
  92         private final static int END_TAG =       0x000020;
  93         private final static int VALUE=          0x000040;
  94         private final static int COMMENT =   0x001000;
  95         private final static int COMMENT_E = 0x002000;
  96         private final static int COMMENT_D1 =0x010000;
  97         private final static int COMMENT_D2 =0x020000;
  98         private final static int COMMENT_D3 =0x040000;
  99         private final static int COMMENT_D4 =0x080000;
 100         // useful combined Comment states
 101         private final static int IN_COMMENT=COMMENT|COMMENT_E|COMMENT_D1|COMMENT_D2;
 102         private final static int COMPLETE_COMMENT = COMMENT|COMMENT_E|COMMENT_D1|COMMENT_D2|COMMENT_D3|COMMENT_D4;
 103
 104
 105         private XEvent parse() throws XMLStreamException {
 106                 Map<String,String> nss = nsses.isEmpty()?null:nsses.peek();
 107
 108                 XEvent rv;
 109                 if((rv=another)!=null) { // "another" is a tag that may have needed to be created, but not
 110                                                                  // immediately returned.  Save for next parse.  If necessary, this could be turned into
 111                                                                  // a FIFO storage, but a single reference is enough for now.
 112                         another = null;      // "rv" is now set for the Event, and will be returned.  Set to Null.
 113                 } else {
 114                         boolean go = true;
 115                         int c=0;
 116
 117                         try {
 118                                 while(go && (c=is.read())>=0) {
 119                                         ++count;
 120                                         switch(c) {
 121                                                 case '<': // Tag is opening
 122                                                         state|=~BEGIN_DOC; // remove BEGIN_DOC flag, this is possibly an XML Doc
 123                                                         XEvent cxe = null;
 124                                                         if(baos.size()>0) { // If there are any characters between tags, we send as Character Event
 125                                                                 String chars = baos.toString().trim();  // Trim out WhiteSpace before and after
 126                                                                 if(chars.length()>0) { // don't send if Characters were only whitespace
 127                                                                         cxe = new XEvent.Characters(chars);
 128                                                                         baos.reset();
 129                                                                         go = false;
 130                                                                 }
 131                                                         }
 132                                                         last = c;  // make sure "last" character is set for use in "ParseTag"
 133                                                         Tag t = parseTag(); // call subroutine to process the tag as a unit
 134                                                         String ns;
 135                                                         switch(t.state&(START_TAG|END_TAG)) {
 136                                                                 case START_TAG:
 137                                                                                 nss = getNss(nss,t);                    // Only Start Tags might have NS Attributes
 138                                                                                                                                                 // Get any NameSpace elements from tag.  If there are, nss will become
 139                                                                                                                                                 // a new Map with all the previous NSs plus the new.  This provides
 140                                                                                                                                                 // scoping behavior when used with the Stack
 141                                                                         // drop through on purpose
 142                                                                 case END_TAG:
 143                                                                         ns = t.prefix==null||nss==null?"":nss.get(t.prefix); // Get the namespace from prefix (if exists)
 144                                                                         break;
 145                                                                 default:
 146                                                                         ns = "";
 147                                                         }
 148                                                         if(ns==null)
 149                                                                 throw new XMLStreamException("Invalid Namespace Prefix at " + count);
 150                                                         go = false;
 151                                                         switch(t.state) { // based on
 152                                                           case DOC_TYPE:
 153                                                                   rv = new XEvent.StartDocument();
 154                                                                   break;
 155                                                           case COMMENT:
 156                                                                   rv = new XEvent.Comment(t.value);
 157                                                                   break;
 158                                                           case START_TAG:
 159                                                                   rv = new XEvent.StartElement(ns,t.name);
 160                                                                   nsses.push(nss);                              // Change potential scope for Namespace
 161                                                                   break;
 162                                                           case END_TAG:
 163                                                                   rv = new XEvent.EndElement(ns,t.name);
 164                                                                   nss = nsses.pop();                    // End potential scope for Namespace
 165                                                                   break;
 166                                                           case START_TAG|END_TAG:                       // This tag is both start/end  aka <myTag/>
 167                                                                   rv = new XEvent.StartElement(ns,t.name);
 168                                                                   if(last=='/')another = new XEvent.EndElement(ns,t.name);
 169                                                         }
 170                                                         if(cxe!=null) {     // if there is a Character Event, it actually should go first.  ow.
 171                                                                 another = rv;   // Make current Event the "another" or next event, and
 172                                                                 rv = cxe;               // send Character Event now
 173                                                         }
 174                                                         break;
 175                                                 case ' ':
 176                                                 case '\t':
 177                                                 case '\n':
 178                                                         if((state&BEGIN_DOC)==BEGIN_DOC) { // if Whitespace before doc, just ignore
 179                                                                 break;
 180                                                         }
 181                                                         // fallthrough on purpose
 182                                                 default:
 183                                                         if((state&BEGIN_DOC)==BEGIN_DOC) { // if there is any data at the start other than XML Tag, it's not XML
 184                                                                 throw new XMLStreamException("Parse Error: This is not an XML Doc");
 185                                                         }
 186                                                         baos.write(c); // save off Characters
 187                                         }
 188                                         last = c; // Some processing needs to know what the last character was, aka Escaped characters... ex \"
 189                                 }
 190                         } catch (IOException e) {
 191                                 throw new XMLStreamException(e); // all errors parsing will be treated as XMLStreamErrors (like StAX)
 192                         }
 193                         if(c==-1 && (state&BEGIN_DOC)==BEGIN_DOC) {                        // Normally, end of stream is ok, however, we need to know if the
 194                                 throw new XMLStreamException("Premature End of File"); // document isn't an XML document, so we throw exception if it
 195                         }                                                                                                                  // hasn't yet been determined to be an XML Doc
 196                 }
 197                 return rv;
 198         }
 199
 200         /**
 201          * parseTag
 202          *
 203          * Parsing a Tag is somewhat complicated, so it's helpful to separate this process from the
 204          * higher level Parsing effort
 205          * @return
 206          * @throws IOException
 207          * @throws XMLStreamException
 208          */
 209         private Tag parseTag() throws IOException, XMLStreamException {
 210                 Tag tag = null;
 211                 boolean go = true;
 212                 state = 0;
 213                 int c, quote=0; // If "quote" is 0, then we're not in a quote.  We set ' (in pretag) or " in attribs accordingly to denote quoted
 214                 String prefix=null,name=null,value=null;
 215                 baos.reset();
 216
 217                 while(go && (c=is.read())>=0) {
 218                         ++count;
 219                         if(quote!=0) { // If we're in a quote, we only end if we hit another quote of the same time, not preceded by \
 220                                 if(c==quote && last!='\\') {
 221                                         quote=0;
 222                                 } else {
 223                                         baos.write(c);
 224                                 }
 225                         } else if((state&COMMENT)==COMMENT) { // similar to Quote is being in a comment
 226                                 switch(c) {
 227                                         case '-':
 228                                                 switch(state) { // XML has a complicated Quote set... <!-- --> ... we keep track if each has been met with flags.
 229                                                         case COMMENT|COMMENT_E:
 230                                                                 state|=COMMENT_D1;
 231                                                                 break;
 232                                                         case COMMENT|COMMENT_E|COMMENT_D1:
 233                                                                 state|=COMMENT_D2;
 234                                                                 baos.reset();                           // clear out "!--", it's a Comment
 235                                                                 break;
 236                                                         case COMMENT|COMMENT_E|COMMENT_D1|COMMENT_D2:
 237                                                                 state|=COMMENT_D3;
 238                                                                 baos.write(c);
 239                                                                 break;
 240                                                         case COMMENT|COMMENT_E|COMMENT_D1|COMMENT_D2|COMMENT_D3:
 241                                                                 state|=COMMENT_D4;
 242                                                                 baos.write(c);
 243                                                                 break;
 244                                                 }
 245                                                 break;
 246                                         case '>': // Tag indicator has been found, do we have all the comment characters in line?
 247                                                 if((state&COMPLETE_COMMENT)==COMPLETE_COMMENT) {
 248                                                         byte ba[] = baos.toByteArray();
 249                                                         tag = new Tag(null,null, new String(ba,0,ba.length-2));
 250                                                         baos.reset();
 251                                                         go = false;
 252                                                         break;
 253                                                 }
 254                                                 // fall through on purpose
 255                                         default:
 256                                                 state&=~(COMMENT_D3|COMMENT_D4);
 257                                                 if((state&IN_COMMENT)!=IN_COMMENT) state&=~IN_COMMENT; // false alarm, it's not actually a comment
 258                                                 baos.write(c);
 259                                 }
 260                         } else { // Normal Tag Processing loop
 261                                 switch(c) {
 262                                         case '?':
 263                                                 switch(state & (QUESTION_F|QUESTION)) {  // Validate the state of Doc tag... <?xml ... ?>
 264                                                         case QUESTION_F:
 265                                                                 state |= DOC_TYPE;
 266                                                                 state &= ~QUESTION_F;
 267                                                                 break;
 268                                                         case 0:
 269                                                                 state |=QUESTION_F;
 270                                                                 break;
 271                                                         default:
 272                                                                 throw new IOException("Bad character [?] at " + count);
 273                                                 }
 274                                                 break;
 275                                         case '!':
 276                                                 if(last=='<') {
 277                                                         state|=COMMENT|COMMENT_E; // likely a comment, continue processing in Comment Loop
 278                                                 }
 279                                                 baos.write(c);
 280                                                 break;
 281                                         case '/':
 282                                                 state|=(last=='<'?END_TAG:(END_TAG|START_TAG));  // end tag indicator </xxx>, ,or both <xxx/>
 283                                                 break;
 284                                         case ':':
 285                                                 prefix=baos.toString(); // prefix indicator
 286                                                 baos.reset();
 287                                                 break;
 288                                         case '=':                                       // used in Attributes
 289                                                 name=baos.toString();
 290                                                 baos.reset();
 291                                                 state|=VALUE;
 292                                                 break;
 293                                         case '>': // end the tag, which causes end of this subprocess as well as formulation of the found data
 294                                                 go = false;
 295                                                 // passthrough on purpose
 296                                         case ' ':
 297                                         case '\t':
 298                                         case '\n': // white space indicates change in internal tag state, ex between name and between attributes
 299                                                 if((state&VALUE)==VALUE) {
 300                                                         value = baos.toString();        // we're in VALUE state, add characters to Value
 301                                                 } else if(name==null) {
 302                                                         name = baos.toString();         // we're in Name state (default) add characters to Name
 303                                                 }
 304                                                 baos.reset();                                   // we've assigned chars, reset buffer
 305                                                 if(name!=null) {                                // Name is not null, there's a tag in the offing here...
 306                                                         Tag t = new Tag(prefix,name,value);
 307                                                         if(tag==null) {                         // Set as the tag to return, if not exists
 308                                                                 tag = t;
 309                                                         } else {                                        // if we already have a Tag, then we'll treat this one as an attribute
 310                                                                 tag.add(t);
 311                                                         }
 312                                                 }
 313                                                 prefix=name=value=null;                 // reset these values in case we loop for attributes.
 314                                                 break;
 315                                         case '\'':                                                      // is the character one of two kinds of quote?
 316                                         case '"':
 317                                                 if(last!='\\') {
 318                                                         quote=c;
 319                                                         break;
 320                                                 }
 321                                                 // Fallthrough ok
 322                                         default:
 323                                                 baos.write(c);                                  // write any unprocessed bytes into buffer
 324
 325                                 }
 326                         }
 327                         last = c;
 328                 }
 329                 int type = state&(DOC_TYPE|COMMENT|END_TAG|START_TAG); // get just the Tag states and turn into Type for Tag
 330                 if(type==0) {
 331                         type=START_TAG;
 332                 }
 333                 if(tag!=null) {
 334                         tag.state|=type;        // add the appropriate Tag States
 335                 }
 336                 return tag;
 337         }
 338
 339         /**
 340          * getNSS
 341          *
 342          * If the tag contains some Namespace attributes, create a new nss from the passed in one, copy all into it, then add
 343          * This provides Scoping behavior
 344          *
 345          * if Nss is null in the first place, create an new nss, so we don't have to deal with null Maps.
 346          *
 347          * @param nss
 348          * @param t
 349          * @return
 350          */
 351         private Map<String, String> getNss(Map<String, String> nss, Tag t) {
 352                 Map<String,String> newnss = null;
 353                 if(t.attribs!=null) {
 354                         for(Tag tag : t.attribs) {
 355                                 if("xmlns".equals(tag.prefix)) {
 356                                         if(newnss==null) {
 357                                                 newnss = new HashMap<>();
 358                                                 if(nss!=null)newnss.putAll(nss);
 359                                         }
 360                                         newnss.put(tag.name, tag.value);
 361                                 }
 362                         }
 363                 }
 364                 //return newnss==null?(nss==null?new HashMap<String,String>():nss):newnss;
 365                 if(newnss==null) {
 366                         if(nss==null) {
 367                                 newnss = new HashMap<>();
 368                         } else {
 369                                 newnss = nss;
 370                         }
 371                 }
 372                 return newnss;
 373         }
 374
 375         /**
 376          * The result of the parseTag method
 377          *
 378          * Data is split up into prefix, name and value portions. "Tags" with Values that are inside a Tag are known in XLM
 379          * as Attributes.
 380          *
 381          * @author Jonathan
 382          *
 383          */
 384         public class Tag {
 385                 public int state;
 386                 public String prefix,name,value;
 387                 public List<Tag> attribs;
 388
 389                 public Tag(String prefix, String name, String value) {
 390                         this.prefix = prefix;
 391                         this.name = name;
 392                         this.value = value;
 393                         attribs = null;
 394                 }
 395
 396                 /**
 397                  * add an attribute
 398                  * Not all tags need attributes... lazy instantiate to save time and memory
 399                  * @param tag
 400                  */
 401                 public void add(Tag attrib) {
 402                         if(attribs == null) {
 403                                 attribs = new ArrayList<>();
 404                         }
 405                         attribs.add(attrib);
 406                 }
 407
 408                 public String toString() {
 409                         StringBuffer sb = new StringBuffer();
 410                         if(prefix!=null) {
 411                                 sb.append(prefix);
 412                                 sb.append(':');
 413                         }
 414                         sb.append(name==null?"!!ERROR!!":name);
 415
 416                         char quote = ((state&DOC_TYPE)==DOC_TYPE)?'\'':'"';
 417                         if(value!=null) {
 418                                 sb.append('=');
 419                                 sb.append(quote);
 420                                 sb.append(value);
 421                                 sb.append(quote);
 422                         }
 423                         return sb.toString();
 424                 }
 425         }
 426
 427 }