Parse links and images

lib/lexer_inline.js

@@ -19,6 +19,7 @@ rules.push(require('./lexer_inline/backticks'));
 //
 //
 rules.push(require('./lexer_inline/emphasis'));
+rules.push(require('./lexer_inline/links'));
 rules.push(require('./lexer_inline/autolink'));
 rules.push(require('./lexer_inline/htmltag'));
 rules.push(require('./lexer_inline/entity'));
@@ -52,9 +53,9 @@ function LexerInline() {
   this.rules = [];
 
   // Rule to skip pure text
-  // - '{$%@' reserved for extentions
+  // - '{$%@}' reserved for extentions
   // - '<>"' added for internal html escaping
-  this.textMatch = /^[^\n\\`*_\[!&{$%@<>"]+/;
+  this.textMatch = /^[^\n\\`*_\[\]!&{}$%@<>"]+/;
 
   for (var i = 0; i < rules.length; i++) {
     this.after(null, rules[i]);

lib/lexer_inline/links.js

@@ -0,0 +1,204 @@
+// Process [links](<to> "stuff")
+
+'use strict';
+
+
+var skipSpaces = require('../helpers').skipSpaces;
+
+
+module.exports = function links(state) {
+  var oldLength,
+      oldPending,
+      level,
+      rules,
+      len,
+      i,
+      ok,
+      found,
+      labelStart,
+      labelEnd,
+      href,
+      title,
+      pos,
+      code,
+      isImage = false,
+      max = state.posMax,
+      start = state.pos,
+      marker = state.src.charCodeAt(start);
+
+  if (marker === 0x21/* ! */) {
+    isImage = true;
+    marker = state.src.charCodeAt(++start);
+  }
+
+  if (marker !== 0x5B/* [ */) { return false; }
+
+  //
+  // Parse link label
+  //
+  oldLength = state.tokens.length;
+  oldPending = state.pending;
+
+  state.pos = start + 1;
+  level = 1;
+  rules = state.lexer.rules;
+  len = rules.length;
+
+  while (state.pos < max) {
+    marker = state.src.charCodeAt(state.pos);
+    if (marker === 0x5B /* [ */) {
+      level++;
+    } else if (marker === 0x5D /* ] */) {
+      level--;
+      if (level === 0) {
+        found = true;
+        break;
+      }
+    }
+
+    for (i = 0; i < len; i++) {
+      // skip emphasis because it has lower priority, compare:
+      //  [foo *bar]()*
+      //  [foo `bar]()`
+      if (rules[i].name !== 'emphasis' && rules[i] !== links) {
+        ok = rules[i](state);
+      }
+      if (ok) { break; }
+    }
+
+    if (!ok) { state.pending += state.src[state.pos++]; }
+  }
+
+  // restore old state
+  labelStart = start + 1;
+  labelEnd = state.pos;
+  state.pos = start;
+  state.tokens.length = oldLength;
+  state.pending = oldPending;
+
+  // parser failed to find ']', so it's not a valid link
+  if (!found) { return false; }
+
+  //
+  // Parse link destination and title
+  //
+  pos = labelEnd + 1;
+  href = title = '';
+  if (pos >= max || state.src.charCodeAt(pos) !== 0x28/* ( */) { return false; }
+
+  // [link](  <href>  "title"  )
+  //        ^^ skipping these spaces
+  pos++;
+  if ((pos = skipSpaces(state, pos)) >= max) { return false; }
+
+  // [link](  <href>  "title"  )
+  //          ^^^^^^ parsing link destination
+  if (state.src.charCodeAt(pos) === 0x3C /* < */) {
+    pos++;
+    while (pos < max) {
+      code = state.src.charCodeAt(pos);
+      if (code === 0x0A /* \n */) { return false; }
+      if (code === 0x3E /* > */) {
+        pos++;
+        break;
+      }
+      if (code === 0x5C /* \ */) {
+        pos++;
+        href += state.src[pos++];
+        continue;
+      }
+
+      href += state.src[pos++];
+    }
+  } else {
+    level = 0;
+    while (pos < max) {
+      code = state.src.charCodeAt(pos);
+
+      if (code === 0x20) { break; }
+
+      // ascii control characters
+      if (code < 0x20 || code === 0x7F) { return false; }
+
+      if (code === 0x5C /* \ */) {
+        pos++;
+        href += state.src[pos++];
+        continue;
+      }
+
+      if (code === 0x28 /* ( */) {
+        level++;
+        if (level > 1) { return false; }
+      }
+
+      if (code === 0x29 /* ) */) {
+        level--;
+        if (level < 0) {
+          break;
+        }
+      }
+
+      href += state.src[pos++];
+    }
+  }
+
+  // [link](  <href>  "title"  )
+  //                ^^ skipping these spaces
+  start = pos;
+  if ((pos = skipSpaces(state, pos)) >= max) { return false; }
+
+  // [link](  <href>  "title"  )
+  //                  ^^^^^^^ parsing link title
+  marker = state.src.charCodeAt(pos);
+  if (start !== pos) {
+    if (marker === 0x22 /* " */ || marker === 0x27 /* ' */ || marker === 0x28 /* ( */) {
+      pos++;
+
+      // if opening marker is "(", switch it to closing marker ")"
+      if (marker === 0x28) { marker = 0x29; }
+
+      while (pos < max) {
+        code = state.src.charCodeAt(pos);
+        if (code === marker) {
+          pos++;
+          break;
+        }
+        if (code === 0x5C /* \ */) {
+          pos++;
+          title += state.src[pos++];
+          continue;
+        }
+
+        title += state.src[pos++];
+      }
+    }
+  }
+
+  // [link](  <href>  "title"  )
+  //                         ^^ skipping these spaces
+  if ((pos = skipSpaces(state, pos)) >= max) { return false; }
+  if (state.src.charCodeAt(pos) !== 0x29/* ) */) { return false; }
+
+  //
+  // We found the end of the link, and know for a fact it's a valid link;
+  // so all that's left to do is to call tokenizer.
+  //
+  state.pos = labelStart;
+  state.posMax = labelEnd;
+  if (state.pending) { state.pushPending(); }
+
+  if (isImage) {
+    state.push({ type: 'image',
+                 src: href,
+                 title: title,
+                 alt: state.src.substr(labelStart, labelEnd - labelStart) });
+  } else {
+    state.push({ type: 'link_open', href: href, title: title });
+    state.lexer.tokenize(state);
+    state.push({ type: 'link_close' });
+  }
+
+  state.pos = pos + 1;
+  state.posMax = max;
+  return true;
+};

lib/renderer.js

@@ -100,13 +100,23 @@ rules.paragraph_close = function (tokens, idx /*, options*/) {
 
 
 rules.link_open = function (tokens, idx /*, options*/) {
-  return '<a href="' + escapeHtmlKeepEntities(tokens[idx].href) + '">';
+  var title = tokens[idx].title ? (' title="' + escapeHtmlKeepEntities(tokens[idx].title) + '"') : '';
+  return '<a href="' + escapeHtmlKeepEntities(tokens[idx].href) + '"' + title + '>';
 };
 rules.link_close = function (/*tokens, idx, options*/) {
   return '</a>';
 };
 
 
+rules.image = function (tokens, idx, options) {
+  var src = ' src="' + escapeHtmlKeepEntities(tokens[idx].src) + '"';
+  var title = tokens[idx].title ? (' title="' + escapeHtmlKeepEntities(tokens[idx].title) + '"') : '';
+  var alt = tokens[idx].alt ? (' alt="' + escapeHtmlKeepEntities(tokens[idx].alt) + '"') : '';
+  var suffix = options.xhtml ? ' /' : '';
+  return '<img' + src + alt + title + suffix + '>';
+};
+
+
 rules.table_open = function (/*tokens, idx, options*/) {
   return '<table>\n';
 };