ozone: xkb: Load keymaps on worker thread & cache them

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc

Index: ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
index a756db9131a69dfdc20747c23bf5f8514021a2f6..5f779753ea292486f951c7cd332152c39ca14c86 100644
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
+++ b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
@@ -6,7 +6,13 @@
 
 #include <xkbcommon/xkbcommon-names.h>
 
+#include "base/bind.h"
+#include "base/location.h"
 #include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+#include "base/task_runner.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/threading/worker_pool.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/keycodes/dom3/dom_code.h"
 #include "ui/events/keycodes/dom3/dom_key.h"
@@ -18,6 +24,10 @@ namespace ui {
 
 namespace {
 
+typedef base::Callback<void(const std::string&,
+                            scoped_ptr<xkb_keymap, XkbKeymapDeleter> keymap)>
+    LoadKeymapCallback;
+
 DomKey CharacterToDomKey(base::char16 character) {
   switch (character) {
     case 0x08:
@@ -616,6 +626,18 @@ const PrintableSimpleEntry kSimpleMap[] = {
     {0x0259, VKEY_OEM_3},      // schwa
 };
 
+void LoadKeymap(const std::string& layout_name,
+                scoped_ptr<xkb_rule_names> names,
+                xkb_context* context,
+                scoped_refptr<base::SingleThreadTaskRunner> reply_runner,
+                const LoadKeymapCallback& reply_callback) {
+  scoped_ptr<xkb_keymap, XkbKeymapDeleter> keymap;
+  keymap.reset(xkb_keymap_new_from_names(context, names.get(),
+                                         XKB_KEYMAP_COMPILE_NO_FLAGS));
+  reply_runner->PostTask(FROM_HERE, base::Bind(reply_callback, layout_name,
+                                               base::Passed(&keymap)));
+}
+
 }  // anonymous namespace
 
 XkbKeyCodeConverter::XkbKeyCodeConverter() {
@@ -626,7 +648,7 @@ XkbKeyCodeConverter::~XkbKeyCodeConverter() {
 
 XkbKeyboardLayoutEngine::XkbKeyboardLayoutEngine(
     const XkbKeyCodeConverter& converter)
-    : key_code_converter_(converter) {
+    : key_code_converter_(converter), weak_ptr_factory_(this) {
   // TODO: add XKB_CONTEXT_NO_ENVIRONMENT_NAMES
   xkb_context_.reset(xkb_context_new(XKB_CONTEXT_NO_DEFAULT_INCLUDES));
   xkb_context_include_path_append(xkb_context_.get(),
@@ -634,6 +656,9 @@ XkbKeyboardLayoutEngine::XkbKeyboardLayoutEngine(
 }
 
 XkbKeyboardLayoutEngine::~XkbKeyboardLayoutEngine() {
+  for (const auto& entry : xkb_keymaps_) {
+    xkb_keymap_unref(entry.keymap);
+  }
 }
 
 bool XkbKeyboardLayoutEngine::CanSetCurrentLayout() const {
@@ -647,6 +672,29 @@ bool XkbKeyboardLayoutEngine::CanSetCurrentLayout() const {
 bool XkbKeyboardLayoutEngine::SetCurrentLayoutByName(
     const std::string& layout_name) {
 #if defined(OS_CHROMEOS)
+  current_layout_name_ = layout_name;
+  for (const auto& entry : xkb_keymaps_) {
+    if (entry.layout_name == layout_name) {
+      SetKeymap(entry.keymap);
+      return true;
+    }
+  }
+  LoadKeymapCallback reply_callback = base::Bind(
+      &XkbKeyboardLayoutEngine::OnKeymapLoaded, weak_ptr_factory_.GetWeakPtr());
+  scoped_ptr<xkb_rule_names> names = GetXkbRuleNames(layout_name);
+  base::WorkerPool::PostTask(
+      FROM_HERE,
+      base::Bind(&LoadKeymap, layout_name, base::Passed(&names),
+                 base::Unretained(xkb_context_.get()),

[spang, 2015/01/06 17:35:50]

..oh dear
 
I didn't look at this closely enough. It doesn't look like xkb_context is thread
safe. Even if it was, posting it to to the WorkerPool inside base::Unretained is
definitely not safe.

+                 base::ThreadTaskRunnerHandle::Get(), reply_callback),
+      true);
+  return true;
+#endif  // defined(OS_CHROMEOS)
+  return false;
+}
+
+scoped_ptr<xkb_rule_names> XkbKeyboardLayoutEngine::GetXkbRuleNames(
+    const std::string& layout_name) {
   size_t dash_index = layout_name.find('-');
   size_t parentheses_index = layout_name.find('(');
   std::string layout_id = layout_name;
@@ -662,22 +710,25 @@ bool XkbKeyboardLayoutEngine::SetCurrentLayoutByName(
     layout_id = layout_name.substr(0, dash_index);
     layout_variant = layout_name.substr(dash_index + 1);
   }
-  struct xkb_rule_names names = {
-    .rules = NULL,
-    .model = "pc101",
-    .layout = layout_id.c_str(),
-    .variant = layout_variant.c_str(),
-    .options = ""
-  };
-  xkb_keymap* keymap = xkb_keymap_new_from_names(xkb_context_.get(),
-                                                 &names,
-                                                 XKB_KEYMAP_COMPILE_NO_FLAGS);
+  return make_scoped_ptr<xkb_rule_names>(
+      new xkb_rule_names{.rules = NULL,
+                         .model = "pc101",
+                         .layout = layout_id.c_str(),
+                         .variant = layout_variant.c_str(),
+                         .options = ""});
+}
+
+void XkbKeyboardLayoutEngine::OnKeymapLoaded(
+    const std::string& layout_name,
+    scoped_ptr<xkb_keymap, XkbKeymapDeleter> keymap) {
   if (keymap) {
-    SetKeymap(keymap);
-    return true;
+    XkbKeymapEntry entry = {layout_name, xkb_keymap_ref(keymap.get())};
+    xkb_keymaps_.push_back(entry);
+    if (layout_name == current_layout_name_)
+      SetKeymap(keymap.get());
+  } else {
+    LOG(ERROR) << "Keymap file fail to load: " << layout_name;
   }
-#endif  // defined(OS_CHROMEOS)
-  return false;
 }
 
 bool XkbKeyboardLayoutEngine::UsesISOLevel5Shift() const {