Plumb through an api to get display cell size from brltty

R=dmazzoni@chromium.org

Test: manual; verify a cell size of 8 on a display, when call chrome.brailleDisplayPrivate.getDisplayState, on a 8-dot celled braille display.
Change-Id: I25a2517e2a6ff29b38746a7ddfb8294669476d9f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2194339
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769511}

chrome/browser/extensions/api/braille_display_private/braille_controller_brlapi.cc

@@ -74,23 +74,17 @@ BrailleControllerImpl::~BrailleControllerImpl() {
 
 void BrailleControllerImpl::TryLoadLibBrlApi() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (libbrlapi_loader_.loaded())
+  if (skip_libbrlapi_so_load_ || libbrlapi_loader_.loaded())
     return;
 
-  // This list of api versions needs to contain the one used by the
-  // corresponding brltty used by Chrome OS for this version of Chrome. For
-  // example, in Chrome OS 84, we use brltty 6.1, which is using brlapi 0.8.
-  // The relevant header is checked into //third_party/libbrlapi/. Ensure to
-  // keep this list in descendning order. Note that we keep older versions so
-  // that tests will continue to work.
-  static const char* const kSupportedVersions[] = {
-      "libbrlapi.so.0.8", "libbrlapi.so.0.7", "libbrlapi.so.0.6",
-      "libbrlapi.so.0.5"};
-  for (size_t i = 0; i < base::size(kSupportedVersions); ++i) {
-    if (libbrlapi_loader_.Load(kSupportedVersions[i]))
-      return;
+  // This api version needs to match the one contained in
+  // third_party/libbrlapi/brlapi.h.
+  static const char* const kSupportedVersion = "libbrlapi.so.0.8";
+
+  if (!libbrlapi_loader_.Load(kSupportedVersion)) {
+    LOG(WARNING) << "Couldn't load libbrlapi(" << kSupportedVersion << ": "
+                 << strerror(errno);
   }
-  LOG(WARNING) << "Couldn't load libbrlapi: " << strerror(errno);
 }
 
 std::unique_ptr<DisplayState> BrailleControllerImpl::GetDisplayState() {
@@ -107,6 +101,10 @@ std::unique_ptr<DisplayState> BrailleControllerImpl::GetDisplayState() {
       display_state->available = true;
       display_state->text_column_count.reset(new int(columns));
       display_state->text_row_count.reset(new int(rows));
+
+      unsigned int cell_size = 0;
+      if (connection_->GetCellSize(&cell_size))
+        display_state->cell_size.reset(new int(cell_size));
     }
   }
   return display_state;
@@ -173,7 +171,7 @@ void BrailleControllerImpl::StartConnecting() {
     return;
   started_connecting_ = true;
   TryLoadLibBrlApi();
-  if (!libbrlapi_loader_.loaded()) {
+  if (!libbrlapi_loader_.loaded() && !skip_libbrlapi_so_load_) {
     return;
   }
 
@@ -235,7 +233,7 @@ void BrailleControllerImpl::OnSocketDirChangedOnIOThread() {
 
 void BrailleControllerImpl::TryToConnect() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  DCHECK(libbrlapi_loader_.loaded());
+  DCHECK(skip_libbrlapi_so_load_ || libbrlapi_loader_.loaded());
   connect_scheduled_ = false;
   if (!connection_.get())
     connection_ = create_brlapi_connection_function_.Run();
@@ -293,7 +291,7 @@ void BrailleControllerImpl::Disconnect() {
 
 std::unique_ptr<BrlapiConnection>
 BrailleControllerImpl::CreateBrlapiConnection() {
-  DCHECK(libbrlapi_loader_.loaded());
+  DCHECK(skip_libbrlapi_so_load_ || libbrlapi_loader_.loaded());
   return BrlapiConnection::Create(&libbrlapi_loader_);
 }
 

chrome/browser/extensions/api/braille_display_private/braille_controller_brlapi.h

@@ -83,6 +83,9 @@ class BrailleControllerImpl : public BrailleController {
   // Manipulated by the SequencedTaskRunner.
   base::FilePathWatcher file_path_watcher_;
 
+  // Set by tests to skip libbrlapi.so loading.
+  bool skip_libbrlapi_so_load_ = false;
+
   friend struct base::DefaultSingletonTraits<BrailleControllerImpl>;
 
   DISALLOW_COPY_AND_ASSIGN(BrailleControllerImpl);

chrome/browser/extensions/api/braille_display_private/braille_display_private_apitest.cc

@@ -50,6 +50,7 @@ struct MockBrlapiConnectionData {
   bool connected;
   size_t display_columns;
   size_t display_rows;
+  size_t cell_size;
   brlapi_error_t error;
   std::vector<std::string> written_content;
   // List of brlapi key codes.  A negative number makes the connection mock
@@ -125,6 +126,11 @@ class MockBrlapiConnection : public BrlapiConnection {
     }
   }
 
+  bool GetCellSize(unsigned int* cell_size) override {
+    *cell_size = data_->cell_size;
+    return true;
+  }
+
  private:
   void NotifyDataReady() {
     on_data_ready_.Run();
@@ -152,6 +158,7 @@ class BrailleDisplayPrivateApiTest : public ExtensionApiTest {
         base::Bind(
             &BrailleDisplayPrivateApiTest::CreateBrlapiConnection,
             base::Unretained(this)));
+    BrailleControllerImpl::GetInstance()->skip_libbrlapi_so_load_ = true;
     DisableAccessibilityManagerBraille();
   }
 
@@ -259,6 +266,7 @@ IN_PROC_BROWSER_TEST_F(BrailleDisplayPrivateApiTest, KeyEvents) {
 IN_PROC_BROWSER_TEST_F(BrailleDisplayPrivateApiTest, DisplayStateChanges) {
   connection_data_.display_columns = 11;
   connection_data_.display_rows = 1;
+  connection_data_.cell_size = 6;
   connection_data_.pending_keys.push_back(kErrorKeyCode);
   connection_data_.reappear_on_disconnect = true;
   ASSERT_TRUE(RunComponentExtensionTest(

chrome/browser/extensions/api/braille_display_private/brlapi_connection.cc

@@ -44,6 +44,7 @@ class BrlapiConnectionImpl : public BrlapiConnection {
   bool GetDisplaySize(unsigned int* rows, unsigned int* columns) override;
   bool WriteDots(const std::vector<unsigned char>& cells) override;
   int ReadKey(brlapi_keyCode_t* keyCode) override;
+  bool GetCellSize(unsigned int* cell_size) override;
 
  private:
   bool CheckConnected();
@@ -180,6 +181,23 @@ int BrlapiConnectionImpl::ReadKey(brlapi_keyCode_t* key_code) {
       handle_.get(), 0 /*wait*/, key_code);
 }
 
+bool BrlapiConnectionImpl::GetCellSize(unsigned int* cell_size) {
+  if (!CheckConnected()) {
+    return false;
+  }
+
+  brlapi_param_deviceCellSize_t device_cell_size;
+  ssize_t result = libbrlapi_loader_->brlapi__getParameter(
+      handle_.get(), BRLAPI_PARAM_DEVICE_CELL_SIZE, 0, BRLAPI_PARAMF_GLOBAL,
+      &device_cell_size, sizeof(device_cell_size));
+
+  if (result == -1 || result != sizeof(device_cell_size))
+    return false;
+
+  *cell_size = device_cell_size;
+  return true;
+}
+
 bool BrlapiConnectionImpl::CheckConnected() {
   if (!handle_) {
     BrlapiError()->brlerrno = BRLAPI_ERROR_ILLEGAL_INSTRUCTION;

chrome/browser/extensions/api/braille_display_private/brlapi_connection.h

@@ -67,6 +67,9 @@ class BrlapiConnection {
   // value.
   virtual int ReadKey(brlapi_keyCode_t* keyCode) = 0;
 
+  // Gets the number of dots in a braille cell.
+  virtual bool GetCellSize(unsigned int* cell_size) = 0;
+
  protected:
   BrlapiConnection();
   DISALLOW_COPY_AND_ASSIGN(BrlapiConnection);

chrome/common/extensions/api/braille_display_private.idl

@@ -56,6 +56,8 @@ namespace brailleDisplayPrivate {
     long? textRowCount;
     // Number of columns of braille cells on the currently connected display.
     long? textColumnCount;
+    // The number of dots in a braille cell on the currently connected display.
+    long? cellSize;
   };
 
   callback DisplayStateCallback = void(DisplayState result);

chrome/test/data/extensions/api_test/braille_display_private/display_state_changes/test.js

@@ -9,9 +9,9 @@ var pass = chrome.test.callbackPass;
 
 var callbackCompleted;
 var EXPECTED_EVENTS = [
-  { "available": true, "textColumnCount": 11, "textRowCount": 1 },
-  { "available": false },
-  { "available": true, "textColumnCount": 22, "textRowCount": 1 },
+  {'available': true, 'textColumnCount': 11, 'textRowCount': 1, cellSize: 6},
+  {'available': false},
+  {'available': true, 'textColumnCount': 22, 'textRowCount': 1, cellSize: 6},
 ];
 
 var eventNumber = 0;

third_party/libbrlapi/BUILD.gn

@@ -23,5 +23,6 @@ generate_library_loader("libbrlapi") {
     "brlapi__leaveTtyMode",
     "brlapi__writeDots",
     "brlapi__readKey",
+    "brlapi__getParameter",
   ]
 }