Bug 1196431 - generalize detectIndentation and move to new file. r=pbro

browser/devtools/sourceeditor/editor.js

@@ -8,14 +8,17 @@
 
 const { Cu, Cc, Ci, components } = require("chrome");
 
-const TAB_SIZE    = "devtools.editor.tabsize";
+const {
+  EXPAND_TAB,
+  TAB_SIZE,
+  DETECT_INDENT,
+  getIndentationFromIteration
+} = require("devtools/toolkit/shared/indentation");
+
 const ENABLE_CODE_FOLDING = "devtools.editor.enableCodeFolding";
-const EXPAND_TAB  = "devtools.editor.expandtab";
 const KEYMAP      = "devtools.editor.keymap";
 const AUTO_CLOSE  = "devtools.editor.autoclosebrackets";
 const AUTOCOMPLETE  = "devtools.editor.autocomplete";
-const DETECT_INDENT = "devtools.editor.detectindentation";
-const DETECT_INDENT_MAX_LINES = 500;
 const L10N_BUNDLE = "chrome://browser/locale/devtools/sourceeditor.properties";
 const XUL_NS      = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const VALID_KEYMAPS = new Set(["emacs", "vim", "sublime"]);
@@ -514,20 +517,15 @@ Editor.prototype = {
   resetIndentUnit: function() {
     let cm = editors.get(this);
 
-    let indentWithTabs = !Services.prefs.getBoolPref(EXPAND_TAB);
-    let indentUnit = Services.prefs.getIntPref(TAB_SIZE);
-    let shouldDetect = Services.prefs.getBoolPref(DETECT_INDENT);
+    let iterFn = function(start, end, callback) {
+      cm.eachLine(start, end, (line) => {
+        return callback(line.text);
+      });
+    };
+
+    let {indentUnit, indentWithTabs} = getIndentationFromIteration(iterFn);
 
     cm.setOption("tabSize", indentUnit);
-
-    if (shouldDetect) {
-      let indent = detectIndentation(this);
-      if (indent != null) {
-        indentWithTabs = indent.tabs;
-        indentUnit = indent.spaces ? indent.spaces : indentUnit;
-      }
-    }
-
     cm.setOption("indentUnit", indentUnit);
     cm.setOption("indentWithTabs", indentWithTabs);
   },
@@ -1300,73 +1298,4 @@ function controller(ed) {
   };
 }
 
-/**
- * Detect the indentation used in an editor. Returns an object
- * with 'tabs' - whether this is tab-indented and 'spaces' - the
- * width of one indent in spaces. Or `null` if it's inconclusive.
- */
-function detectIndentation(ed) {
-  let cm = editors.get(ed);
-
-  let spaces = {};  // # spaces indent -> # lines with that indent
-  let last = 0;     // indentation width of the last line we saw
-  let tabs = 0;     // # of lines that start with a tab
-  let total = 0;    // # of indented lines (non-zero indent)
-
-  cm.eachLine(0, DETECT_INDENT_MAX_LINES, (line) => {
-    let text = line.text;
-
-    if (text.startsWith("\t")) {
-      tabs++;
-      total++;
-      return;
-    }
-    let width = 0;
-    while (text[width] === " ") {
-      width++;
-    }
-    // don't count lines that are all spaces
-    if (width == text.length) {
-      last = 0;
-      return;
-    }
-    if (width > 1) {
-      total++;
-    }
-
-    // see how much this line is offset from the line above it
-    let indent = Math.abs(width - last);
-    if (indent > 1 && indent <= 8) {
-      spaces[indent] = (spaces[indent] || 0) + 1;
-    }
-    last = width;
-  });
-
-  // this file is not indented at all
-  if (total == 0) {
-    return null;
-  }
-
-  // mark as tabs if they start more than half the lines
-  if (tabs >= total / 2) {
-    return { tabs: true };
-  }
-
-  // find most frequent non-zero width difference between adjacent lines
-  let freqIndent = null, max = 1;
-  for (let width in spaces) {
-    width = parseInt(width, 10);
-    let tally = spaces[width];
-    if (tally > max) {
-      max = tally;
-      freqIndent = width;
-    }
-  }
-  if (!freqIndent) {
-    return null;
-  }
-
-  return { tabs: false, spaces: freqIndent };
-}
-
 module.exports = Editor;

toolkit/devtools/shared/indentation.js

@@ -0,0 +1,161 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2; fill-column: 80 -*- */
+/* vim:set ts=2 sw=2 sts=2 et tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { Cu } = require("chrome");
+Cu.import("resource://gre/modules/Services.jsm");
+
+const EXPAND_TAB = "devtools.editor.expandtab";
+const TAB_SIZE = "devtools.editor.tabsize";
+const DETECT_INDENT = "devtools.editor.detectindentation";
+const DETECT_INDENT_MAX_LINES = 500;
+
+/**
+ * Get the indentation to use in an editor, or return false if the user has
+ * asked for the indentation to be guessed from some text.
+ *
+ * @return {false | Object}
+ *        Returns false if the "detect indentation" pref is set.
+ *        an object of the form {indentUnit, indentWithTabs}.
+ *        |indentUnit| is the number of indentation units to use
+ *        to indent a "block".
+ *        |indentWithTabs| is a boolean which is true if indentation
+ *        should be done using tabs.
+ */
+function getIndentationFromPrefs() {
+  let shouldDetect = Services.prefs.getBoolPref(DETECT_INDENT);
+  if (shouldDetect) {
+    return false;
+  }
+
+  let indentWithTabs = !Services.prefs.getBoolPref(EXPAND_TAB);
+  let indentUnit = Services.prefs.getIntPref(TAB_SIZE);
+  return {indentUnit, indentWithTabs};
+}
+
+/**
+ * Given a function that can iterate over some text, compute the indentation to
+ * use.  This consults various prefs to arrive at a decision.
+ *
+ * @param {Function} iterFunc A function of three arguments:
+ *        (start, end, callback); where |start| and |end| describe
+ *        the range of text lines to examine, and |callback| is a function
+ *        to be called with the text of each line.
+ *
+ * @return {Object} an object of the form {indentUnit, indentWithTabs}.
+ *        |indentUnit| is the number of indentation units to use
+ *        to indent a "block".
+ *        |indentWithTabs| is a boolean which is true if indentation
+ *        should be done using tabs.
+ */
+function getIndentationFromIteration(iterFunc) {
+  let indentWithTabs = !Services.prefs.getBoolPref(EXPAND_TAB);
+  let indentUnit = Services.prefs.getIntPref(TAB_SIZE);
+  let shouldDetect = Services.prefs.getBoolPref(DETECT_INDENT);
+
+  if (shouldDetect) {
+    let indent = detectIndentation(iterFunc);
+    if (indent != null) {
+      indentWithTabs = indent.tabs;
+      indentUnit = indent.spaces ? indent.spaces : indentUnit;
+    }
+  }
+
+  return {indentUnit, indentWithTabs};
+}
+
+/**
+ * A wrapper for @see getIndentationFromIteration which computes the
+ * indentation of a given string.
+ *
+ * @param {String} string the input text
+ * @return {Object} an object of the same form as returned by
+ *                  getIndentationFromIteration
+ */
+function getIndentationFromString(string) {
+  let iteratorFn = function(start, end, callback) {
+    let split = string.split(/\r\n|\r|\n|\f/);
+    split.slice(start, end).forEach(callback);
+  };
+  return getIndentationFromIteration(iteratorFn);
+}
+
+/**
+ * Detect the indentation used in an editor. Returns an object
+ * with 'tabs' - whether this is tab-indented and 'spaces' - the
+ * width of one indent in spaces. Or `null` if it's inconclusive.
+ */
+function detectIndentation(textIteratorFn) {
+  // # spaces indent -> # lines with that indent
+  let spaces = {};
+  // indentation width of the last line we saw
+  let last = 0;
+  // # of lines that start with a tab
+  let tabs = 0;
+  // # of indented lines (non-zero indent)
+  let total = 0;
+
+  textIteratorFn(0, DETECT_INDENT_MAX_LINES, (text) => {
+    if (text.startsWith("\t")) {
+      tabs++;
+      total++;
+      return;
+    }
+    let width = 0;
+    while (text[width] === " ") {
+      width++;
+    }
+    // don't count lines that are all spaces
+    if (width == text.length) {
+      last = 0;
+      return;
+    }
+    if (width > 1) {
+      total++;
+    }
+
+    // see how much this line is offset from the line above it
+    let indent = Math.abs(width - last);
+    if (indent > 1 && indent <= 8) {
+      spaces[indent] = (spaces[indent] || 0) + 1;
+    }
+    last = width;
+  });
+
+  // this file is not indented at all
+  if (total == 0) {
+    return null;
+  }
+
+  // mark as tabs if they start more than half the lines
+  if (tabs >= total / 2) {
+    return { tabs: true };
+  }
+
+  // find most frequent non-zero width difference between adjacent lines
+  let freqIndent = null, max = 1;
+  for (let width in spaces) {
+    width = parseInt(width, 10);
+    let tally = spaces[width];
+    if (tally > max) {
+      max = tally;
+      freqIndent = width;
+    }
+  }
+  if (!freqIndent) {
+    return null;
+  }
+
+  return { tabs: false, spaces: freqIndent };
+}
+
+exports.EXPAND_TAB = EXPAND_TAB;
+exports.TAB_SIZE = TAB_SIZE;
+exports.DETECT_INDENT = DETECT_INDENT;
+exports.getIndentationFromPrefs = getIndentationFromPrefs;
+exports.getIndentationFromIteration = getIndentationFromIteration;
+exports.getIndentationFromString = getIndentationFromString;

toolkit/devtools/shared/moz.build

@@ -5,10 +5,12 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 BROWSER_CHROME_MANIFESTS += ['tests/browser/browser.ini']
+XPCSHELL_TESTS_MANIFESTS += ['tests/unit/xpcshell.ini']
 
 EXTRA_JS_MODULES.devtools.shared += [
   'async-storage.js',
   'framerate.js',
+  'indentation.js',
   'memory.js',
   'profiler.js',
   'system.js',

toolkit/devtools/shared/tests/unit/.eslintrc

@@ -0,0 +1,4 @@
+{
+  // Extend from the common devtools xpcshell eslintrc config.
+  "extends": "../../../../../browser/devtools/.eslintrc.xpcshell"
+}

toolkit/devtools/shared/tests/unit/test_indentation.js

@@ -0,0 +1,135 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const Cu = Components.utils;
+const {require} = Cu.import("resource://gre/modules/devtools/Loader.jsm");
+const Services = require("Services");
+const {
+  EXPAND_TAB,
+  TAB_SIZE,
+  DETECT_INDENT,
+  getIndentationFromPrefs,
+  getIndentationFromIteration,
+  getIndentationFromString,
+} = require("devtools/toolkit/shared/indentation");
+
+function test_indent_from_prefs() {
+  Services.prefs.setBoolPref(DETECT_INDENT, true);
+  equal(getIndentationFromPrefs(), false,
+        "getIndentationFromPrefs returning false");
+
+  Services.prefs.setIntPref(TAB_SIZE, 73);
+  Services.prefs.setBoolPref(EXPAND_TAB, false);
+  Services.prefs.setBoolPref(DETECT_INDENT, false);
+  deepEqual(getIndentationFromPrefs(), {indentUnit: 73, indentWithTabs: true},
+            "getIndentationFromPrefs basic test");
+}
+
+const TESTS = [
+  {
+    desc: "two spaces",
+    input: [
+      "/*",
+      " * tricky comment block",
+      " */",
+      "div {",
+      "  color: red;",
+      "  background: blue;",
+      "}",
+      "     ",
+      "span {",
+      "  padding-left: 10px;",
+      "}"
+    ],
+    expected: {indentUnit: 2, indentWithTabs: false}
+  },
+  {
+    desc: "four spaces",
+    input: [
+      "var obj = {",
+      "    addNumbers: function() {",
+      "        var x = 5;",
+      "        var y = 18;",
+      "        return x + y;",
+      "    },",
+      "   ",
+      "    /*",
+      "     * Do some stuff to two numbers",
+      "     * ",
+      "     * @param x",
+      "     * @param y",
+      "     * ",
+      "     * @return the result of doing stuff",
+      "     */",
+      "    subtractNumbers: function(x, y) {",
+      "        var x += 7;",
+      "        var y += 18;",
+      "        var result = x - y;",
+      "        result %= 2;",
+      "    }",
+      "}"
+    ],
+    expected: {indentUnit: 4, indentWithTabs: false}
+  },
+  {
+    desc: "tabs",
+    input: [
+      "/*",
+      " * tricky comment block",
+      " */",
+      "div {",
+      "\tcolor: red;",
+      "\tbackground: blue;",
+      "}",
+      "",
+      "span {",
+      "\tpadding-left: 10px;",
+      "}"
+    ],
+    expected: {indentUnit: 2, indentWithTabs: true}
+  },
+  {
+    desc: "no indent",
+    input: [
+      "var x = 0;",
+      "           // stray thing",
+      "var y = 9;",
+      "    ",
+      ""
+    ],
+    expected: {indentUnit: 2, indentWithTabs: false}
+  },
+];
+
+function test_indent_detection() {
+  Services.prefs.setIntPref(TAB_SIZE, 2);
+  Services.prefs.setBoolPref(EXPAND_TAB, true);
+  Services.prefs.setBoolPref(DETECT_INDENT, true);
+
+  for (let test of TESTS) {
+    let iterFn = function(start, end, callback) {
+      test.input.slice(start, end).forEach(callback);
+    };
+
+    deepEqual(getIndentationFromIteration(iterFn), test.expected,
+              "test getIndentationFromIteration " + test.desc);
+  }
+
+  for (let test of TESTS) {
+    deepEqual(getIndentationFromString(test.input.join("\n")), test.expected,
+              "test getIndentationFromString " + test.desc);
+  }
+}
+
+function run_test() {
+  try {
+    test_indent_from_prefs();
+    test_indent_detection();
+  } finally {
+    Services.prefs.clearUserPref(TAB_SIZE);
+    Services.prefs.clearUserPref(EXPAND_TAB);
+    Services.prefs.clearUserPref(DETECT_INDENT);
+  }
+}

toolkit/devtools/shared/tests/unit/xpcshell.ini

@@ -0,0 +1,5 @@
+[DEFAULT]
+head =
+tail =
+
+[test_indentation.js]