1 files changed, 239 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/ui/state.js b/toolkit/jetpack/sdk/ui/state.js
new file mode 100644
index 000000000..152ce696d
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+++ b/toolkit/jetpack/sdk/ui/state.js
@@ -0,0 +1,239 @@
+/* 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';
+
+// The Button module currently supports only Firefox.
+// See: https://bugzilla.mozilla.org/show_bug.cgi?id=jetpack-panel-apps
+module.metadata = {
+  'stability': 'experimental',
+  'engines': {
+    'Firefox': '*',
+    'SeaMonkey': '*',
+    'Thunderbird': '*'
+  }
+};
+
+const { Ci } = require('chrome');
+
+const events = require('../event/utils');
+const { events: browserEvents } = require('../browser/events');
+const { events: tabEvents } = require('../tab/events');
+const { events: stateEvents } = require('./state/events');
+
+const { windows, isInteractive, getFocusedBrowser } = require('../window/utils');
+const { getActiveTab, getOwnerWindow } = require('../tabs/utils');
+
+const { ignoreWindow } = require('../private-browsing/utils');
+
+const { freeze } = Object;
+const { merge } = require('../util/object');
+const { on, off, emit } = require('../event/core');
+
+const { add, remove, has, clear, iterator } = require('../lang/weak-set');
+const { isNil } = require('../lang/type');
+
+const { viewFor } = require('../view/core');
+
+const components = new WeakMap();
+
+const ERR_UNREGISTERED = 'The state cannot be set or get. ' +
+  'The object may be not be registered, or may already have been unloaded.';
+
+const ERR_INVALID_TARGET = 'The state cannot be set or get for this target.' +
+  'Only window, tab and registered component are valid targets.';
+
+const isWindow = thing => thing instanceof Ci.nsIDOMWindow;
+const isTab = thing => thing.tagName && thing.tagName.toLowerCase() === 'tab';
+const isActiveTab = thing => isTab(thing) && thing === getActiveTab(getOwnerWindow(thing));
+const isEnumerable = window => !ignoreWindow(window);
+const browsers = _ =>
+  windows('navigator:browser', { includePrivate: true }).filter(isInteractive);
+const getMostRecentTab = _ => getActiveTab(getFocusedBrowser());
+
+function getStateFor(component, target) {
+  if (!isRegistered(component))
+    throw new Error(ERR_UNREGISTERED);
+
+  if (!components.has(component))
+    return null;
+
+  let states = components.get(component);
+
+  if (target) {
+    if (isTab(target) || isWindow(target) || target === component)
+      return states.get(target) || null;
+    else
+      throw new Error(ERR_INVALID_TARGET);
+  }
+
+  return null;
+}
+exports.getStateFor = getStateFor;
+
+function getDerivedStateFor(component, target) {
+  if (!isRegistered(component))
+    throw new Error(ERR_UNREGISTERED);
+
+  if (!components.has(component))
+    return null;
+
+  let states = components.get(component);
+
+  let componentState = states.get(component);
+  let windowState = null;
+  let tabState = null;
+
+  if (target) {
+    // has a target
+    if (isTab(target)) {
+      windowState = states.get(getOwnerWindow(target), null);
+
+      if (states.has(target)) {
+        // we have a tab state
+        tabState = states.get(target);
+      }
+    }
+    else if (isWindow(target) && states.has(target)) {
+      // we have a window state
+      windowState = states.get(target);
+    }
+  }
+
+  return freeze(merge({}, componentState, windowState, tabState));
+}
+exports.getDerivedStateFor = getDerivedStateFor;
+
+function setStateFor(component, target, state) {
+  if (!isRegistered(component))
+    throw new Error(ERR_UNREGISTERED);
+
+  let isComponentState = target === component;
+  let targetWindows = isWindow(target) ? [target] :
+                      isActiveTab(target) ? [getOwnerWindow(target)] :
+                      isComponentState ? browsers() :
+                      isTab(target) ? [] :
+                      null;
+
+  if (!targetWindows)
+    throw new Error(ERR_INVALID_TARGET);
+
+  // initialize the state's map
+  if (!components.has(component))
+    components.set(component, new WeakMap());
+
+  let states = components.get(component);
+
+  if (state === null && !isComponentState) // component state can't be deleted
+    states.delete(target);
+  else {
+    let base = isComponentState ? states.get(target) : null;
+    states.set(target, freeze(merge({}, base, state)));
+  }
+
+  render(component, targetWindows);
+}
+exports.setStateFor = setStateFor;
+
+function render(component, targetWindows) {
+  targetWindows = targetWindows ? [].concat(targetWindows) : browsers();
+
+  for (let window of targetWindows.filter(isEnumerable)) {
+    let tabState = getDerivedStateFor(component, getActiveTab(window));
+
+    emit(stateEvents, 'data', {
+      type: 'render',
+      target: component,
+      window: window,
+      state: tabState
+    });
+
+  }
+}
+exports.render = render;
+
+function properties(contract) {
+  let { rules } = contract;
+  let descriptor = Object.keys(rules).reduce(function(descriptor, name) {
+    descriptor[name] = {
+      get: function() { return getDerivedStateFor(this)[name] },
+      set: function(value) {
+        let changed = {};
+        changed[name] = value;
+
+        setStateFor(this, this, contract(changed));
+      }
+    }
+    return descriptor;
+  }, {});
+
+  return Object.create(Object.prototype, descriptor);
+}
+exports.properties = properties;
+
+function state(contract) {
+  return {
+    state: function state(target, state) {
+      let nativeTarget = target === 'window' ? getFocusedBrowser()
+                          : target === 'tab' ? getMostRecentTab()
+                          : target === this ? null
+                          : viewFor(target);
+
+      if (!nativeTarget && target !== this && !isNil(target))
+        throw new Error(ERR_INVALID_TARGET);
+
+      target = nativeTarget || target;
+
+      // jquery style
+      return arguments.length < 2
+        ? getDerivedStateFor(this, target)
+        : setStateFor(this, target, contract(state))
+    }
+  }
+}
+exports.state = state;
+
+const register = (component, state) => {
+  add(components, component);
+  setStateFor(component, component, state);
+}
+exports.register = register;
+
+const unregister = component => {
+  remove(components, component);
+}
+exports.unregister = unregister;
+
+const isRegistered = component => has(components, component);
+exports.isRegistered = isRegistered;
+
+var tabSelect = events.filter(tabEvents, e => e.type === 'TabSelect');
+var tabClose = events.filter(tabEvents, e => e.type === 'TabClose');
+var windowOpen = events.filter(browserEvents, e => e.type === 'load');
+var windowClose = events.filter(browserEvents, e => e.type === 'close');
+
+var close = events.merge([tabClose, windowClose]);
+var activate = events.merge([windowOpen, tabSelect]);
+
+on(activate, 'data', ({target}) => {
+  let [window, tab] = isWindow(target)
+                        ? [target, getActiveTab(target)]
+                        : [getOwnerWindow(target), target];
+
+  if (ignoreWindow(window)) return;
+
+  for (let component of iterator(components)) {
+    emit(stateEvents, 'data', {
+      type: 'render',
+      target: component,
+      window: window,
+      state: getDerivedStateFor(component, tab)
+    });
+  }
+});
+
+on(close, 'data', function({target}) {
+  for (let component of iterator(components)) {
+    components.get(component).delete(target);
+  }
+});