Add the github-linguist package

This commit only adds a single package and all of its transitive
dependencies. The github-linguist package will be used for counting
lines of code as a baseline for databases we are analyzing.

node_modules/github-linguist/src/languages.ts

@@ -0,0 +1,176 @@
+import { ExtensionJustify } from './utils';
+
+// tslint:disable-next-line
+const languageMap = require('language-map');
+// tslint:disable-next-line
+// const lang = require('language-classifier');
+
+interface ExtensionsTypes {
+  [key: string]: string;
+}
+
+export interface DetectorOptions {}
+
+/**
+ * detecte program language through file extension
+ *
+ * @export
+ * @class LanguageDetector
+ */
+export class Languages {
+  extensionMap: {
+    [key: string]: string;
+  } = {};
+
+  /**
+   * Creates an instance of Detector.
+   */
+  constructor() {
+    this.extensionMap = this.loadExtensionMap();
+  }
+
+  /**
+   * load language before detecting
+   */
+  private loadExtensionMap = () => {
+    const extensions: ExtensionsTypes = {};
+
+    Object.keys(languageMap).forEach((language) => {
+      const languageMode = languageMap[language];
+      const languageExtensions = (languageMode && languageMode.extensions) || [];
+      languageExtensions.forEach((extension: string) => {
+        extensions[extension.toLowerCase()] = language.toLowerCase();
+      });
+    });
+
+    return Object.assign({}, extensions, ExtensionJustify);
+  }
+
+  /**
+   * Retrieve the regular expressions for a given language.
+   * This is incomplete, but covers most of the languages we
+   * see in the wild.
+   *
+   * @param language the language to retrieve regexes for
+   */
+  public getRegexes(language: string): Regexes {
+    switch(language) {
+      case 'html':
+      case 'xml':
+        return ALL_REGEXES.html;
+
+      case 'ruby':
+        return ALL_REGEXES.ruby;
+
+      case 'python':
+        return ALL_REGEXES.python;
+
+      default:
+        // not exact, but likely the best guess for any other unspecified language.
+        return ALL_REGEXES.c;
+    }
+  }
+
+  /**
+   * return extension map
+   */
+  public getExtensionMap() {
+    return this.extensionMap;
+  }
+}
+
+export interface Regexes {
+  singleLineComment: RegExp;
+  multiLineCommentOpen: RegExp;
+  multiLineCommentOpenStart: RegExp;
+  multiLineCommentClose: RegExp;
+  multiLineCommentCloseEnd: RegExp;
+  multiLineCommentOpenAndClose: RegExp;
+}
+
+const ALL_REGEXES: Record<string, Regexes> = {
+  c: {
+    // matches when // are the first two characters of a line
+    singleLineComment: /^\/\//,
+
+    // matches when /* exists in a line
+    multiLineCommentOpen: /\/\*/,
+
+    // matches when /* starts a line
+    multiLineCommentOpenStart: /^\/\*/,
+
+    // matches when */ exists a line
+    multiLineCommentClose: /\*\//,
+
+    // matches when */ ends a line
+    multiLineCommentCloseEnd: /\*\/$/,
+
+    // matches /* ... */
+    multiLineCommentOpenAndClose: /\/\*.*\*\//
+  },
+
+  python: {
+    // matches when # the first character of a line
+    singleLineComment: /^#/,
+
+    // matches when """ starts a line. This is not right, since
+    // a multiline string is not always a comment, but for the
+    // sake of simplicity, we will do that here.
+    multiLineCommentOpen: /"""/,
+
+    // matches when """ starts a line
+    multiLineCommentOpenStart: /^"""/,
+
+    // matches when """ exists in a line
+    multiLineCommentClose: /"""/,
+
+    // matches when """ ends a line
+    multiLineCommentCloseEnd: /"""$/,
+
+    // matches """ ... """
+    multiLineCommentOpenAndClose: /""".*"""/
+  },
+
+  ruby: {
+    // matches when # the first character of a line
+    singleLineComment: /^#/,
+
+    // For ruby multiline comments, =begin and =end must be
+    // on their own lines
+
+    // matches when =begin starts a line
+    multiLineCommentOpen: /^=begin/,
+
+    // matches when "begin starts a line
+    multiLineCommentOpenStart: /^=begin/,
+
+    // matches when "end ends a line
+    multiLineCommentClose: /^=end/,
+
+    // matches when "end ends a line
+    multiLineCommentCloseEnd: /^=end$/,
+
+    // not possible in ruby
+    multiLineCommentOpenAndClose: /^\0$/
+  },
+
+  html: {
+    // There is no single line comment
+    singleLineComment: /^\0$/,
+
+    // matches when =begin starts a line
+    multiLineCommentOpen: /<!--/,
+
+    // matches when "begin starts a line
+    multiLineCommentOpenStart: /^<!--/,
+
+    // matches when "end ends a line
+    multiLineCommentClose: /-->/,
+
+    // matches when "end ends a line
+    multiLineCommentCloseEnd: /-->$/,
+
+    // matches <!-- ... -->
+    multiLineCommentOpenAndClose: /<!--.*-->/
+  }
+};