'Find-as-you-type'-search in dartdoc/apidoc.

pkg/dartdoc/search.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/**
+ * [SearchText] represent the search field text. The text is viewed in three
+ * ways: [text] holds the original search text, used for performing
+ * case-sensitive matches, [lowerCase] holds the lower-case search text, used
+ * for performing case-insenstive matches, [camelCase] holds a camel-case
+ * interpretation of the search text, used to order matches in camel-case.
+ */
+class SearchText {
+  final String text;
+  final String lowerCase;
+  final String camelCase;
+
+  SearchText(String searchText)
+      : text = searchText,
+        lowerCase = searchText.toLowerCase(),
+        camelCase = searchText.isEmpty() ? ''
+            : '${searchText.substring(0, 1).toUpperCase()}'
+              '${searchText.substring(1)}';
+
+  int get length() => text.length;
+
+  bool isEmpty() => length == 0;
+}
+
+/**
+ * [StringMatch] represents the case-insensitive matching of [searchText] as a
+ * substring within a [text].
+ */
+class StringMatch {
+  final SearchText searchText;
+  final String text;
+  final int matchOffset;
+  final int matchEnd;
+
+  StringMatch(this.searchText,
+              this.text, this.matchOffset, this.matchEnd);
+
+  /**
+   * Returns the HTML representation of the match.
+   */
+  String toHtml() {
+    return '${text.substring(0, matchOffset)}'
+           '<span class="drop-down-link-highlight">$matchText</span>'
+           '${text.substring(matchEnd)}';
+  }
+
+  String get matchText() =>
+      text.substring(matchOffset, matchEnd);
+
+  /**
+   * Is [:true:] iff [searchText] matches the full [text] case-sensitively.
+   */
+  bool get isFullMatch() => text == searchText.text;
+
+  /**
+   * Is [:true:] iff [searchText] matches a substring of [text]
+   * case-sensitively.
+   */
+  bool get isExactMatch() => matchText == searchText.text;
+
+  /**
+   * Is [:true:] iff [searchText] matches a substring of [text] when
+   * [searchText] is interpreted as camel case.
+   */
+  bool get isCamelCaseMatch() => matchText == searchText.camelCase;
+}
+
+/**
+ * [Result] represents a match of the search text on a library, type or member.
+ */
+class Result {
+  final StringMatch prefix;
+  final StringMatch match;
+
+  final String library;
+  final String type;
+  final String args;
+  final String kind;
+  final String url;
+
+  TableRowElement row;
+
+  Result(this.match, this.kind, this.url,
+         [this.library, this.type, String args, this.prefix])
+      : this.args = args != null ? '&lt;$args&gt;' : '';
+
+  bool get isTopLevel() => prefix == null && type == null;
+
+  void addRow(TableElement table) {
+    if (row != null) return;
+
+    clickHandler(Event event) {
+      window.location.href = url;
+      hideDropDown();
+    }
+
+    row = table.insertRow(table.rows.length);
+    row.classes.add('drop-down-link-tr');
+    row.on.mouseDown.add((event) => hideDropDownSuspend = true);
+    row.on.click.add(clickHandler);
+    row.on.mouseUp.add((event) => hideDropDownSuspend = false);
+    var sb = new StringBuffer();
+    sb.add('<td class="drop-down-link-td">');
+    sb.add('<table class="drop-down-table"><tr><td colspan="2">');
+    if (kind == GETTER) {
+      sb.add('get ');
+    } else if (kind == SETTER) {
+      sb.add('set ');
+    }
+    sb.add(match.toHtml());
+    if (kind == CLASS || kind == INTERFACE || kind == TYPEDEF) {
+      sb.add(args);
+    } else if (kind == CONSTRUCTOR || kind == METHOD) {
+      sb.add('(...)');
+    }
+    sb.add('</td></tr><tr><td class="drop-down-link-kind">');
+    sb.add(kindToString(kind));
+    if (prefix != null) {
+      sb.add(' in ');
+      sb.add(prefix.toHtml());
+      sb.add(args);
+    } else if (type != null) {
+      sb.add(' in ');
+      sb.add(type);
+      sb.add(args);
+    }
+
+    sb.add('</td><td class="drop-down-link-library">');
+    if (library != null) {
+      sb.add('library $library');
+    }
+    sb.add('</td></tr></table></td>');
+    row.innerHTML = sb.toString();
+  }
+}
+
+/**
+ * Creates a [StringMatch] object for [text] if a substring matches
+ * [searchText], or returns [: null :] if no match is found.
+ */
+StringMatch obtainMatch(SearchText searchText, String text) {
+  if (searchText.isEmpty()) {
+    return new StringMatch(searchText, text, 0, 0);
+  }
+  int offset = text.toLowerCase().indexOf(searchText.lowerCase);
+  if (offset != -1) {
+    return new StringMatch(searchText, text,
+                           offset, offset + searchText.length);
+  }
+  return null;
+}
+
+/**
+ * Compares [a] and [b], regarding [:true:] smaller than [:false:].
+ *
+ * [:null:]-values are not handled.
+ */
+int compareBools(bool a, bool b) {
+  if (a == b) return 0;
+  return a ? -1 : 1;
+}
+
+/**
+ * Used to sort the search results heuristically to show the more relevant match
+ * in the top of the dropdown.
+ */
+int resultComparator(Result a, Result b) {
+  // Favor top level entities.
+  int result = compareBools(a.isTopLevel, b.isTopLevel);
+  if (result != 0) return result;
+
+  if (a.prefix != null && b.prefix != null) {
+    // Favor full prefix matches.
+    result = compareBools(a.prefix.isFullMatch, b.prefix.isFullMatch);
+    if (result != 0) return result;
+  }
+
+  // Favor matches in the start.
+  result = compareBools(a.match.matchOffset == 0,
+                        b.match.matchOffset == 0);
+  if (result != 0) return result;
+
+  // Favor matches to the end. For example, prefer 'cancel' over 'cancelable'
+  result = compareBools(a.match.matchEnd == a.match.text.length,
+                        b.match.matchEnd == b.match.text.length);
+  if (result != 0) return result;
+
+  // Favor exact case-sensitive matches.
+  result = compareBools(a.match.isExactMatch, b.match.isExactMatch);
+  if (result != 0) return result;
+
+  // Favor matches that do not break camel-case.
+  result = compareBools(a.match.isCamelCaseMatch, b.match.isCamelCaseMatch);
+  if (result != 0) return result;
+
+  // Favor matches close to the begining.
+  result = a.match.matchOffset.compareTo(b.match.matchOffset);
+  if (result != 0) return result;
+
+  if (a.type != null && b.type != null) {
+    // Favor short type names over long.
+    result = a.type.length.compareTo(b.type.length);
+    if (result != 0) return result;
+
+    // Sort type alphabetically.
+    // TODO(4805): Use [:type.compareToIgnoreCase] when supported.
+    result = a.type.toLowerCase().compareTo(b.type.toLowerCase());
+    if (result != 0) return result;
+  }
+
+  // Sort match alphabetically.
+  // TODO(4805): Use [:text.compareToIgnoreCase] when supported.
+  return a.match.text.toLowerCase().compareTo(b.match.text.toLowerCase());
+}