Reland of Update device/usb and its Mojo interface for variable size ISO packets.

extensions/browser/api/usb/usb_api.cc

Index: extensions/browser/api/usb/usb_api.cc
diff --git a/extensions/browser/api/usb/usb_api.cc b/extensions/browser/api/usb/usb_api.cc
index 16710ddabbba41f9b003f5c6fed7d5b4cd442720..303523964fe927b17fff7499a5e2ef08532c86a5 100644
--- a/extensions/browser/api/usb/usb_api.cc
+++ b/extensions/browser/api/usb/usb_api.cc
@@ -4,6 +4,8 @@
 
 #include "extensions/browser/api/usb/usb_api.h"
 
+#include <algorithm>
+#include <numeric>
 #include <string>
 #include <utility>
 #include <vector>
@@ -468,7 +470,8 @@ void UsbTransferFunction::OnCompleted(UsbTransferStatus status,
   } else {
     scoped_ptr<base::ListValue> error_args(new base::ListValue());
     error_args->Append(std::move(transfer_info));
-    // Returning arguments with an error is wrong but we're stuck with it.
+    // Using ErrorWithArguments is discouraged but required to provide the
+    // detailed transfer info as the transfer may have partially succeeded.
     Respond(ErrorWithArguments(std::move(error_args),
                                ConvertTransferStatusToApi(status)));
   }
@@ -1134,48 +1137,89 @@ ExtensionFunction::ResponseAction UsbIsochronousTransferFunction::Run() {
   size_t size = 0;
   UsbEndpointDirection direction = device::USB_DIRECTION_INBOUND;
 
-  if (!ConvertDirectionFromApi(generic_transfer.direction, &direction)) {
+  if (!ConvertDirectionFromApi(generic_transfer.direction, &direction))
     return RespondNow(Error(kErrorConvertDirection));
-  }
 
-  if (!GetTransferSize(generic_transfer, &size)) {
+  if (!GetTransferSize(generic_transfer, &size))
     return RespondNow(Error(kErrorInvalidTransferLength));
-  }
 
-  if (transfer.packets < 0 || transfer.packets >= kMaxPackets) {
+  if (transfer.packets < 0 || transfer.packets >= kMaxPackets)
     return RespondNow(Error(kErrorInvalidNumberOfPackets));
-  }
+  size_t packets = transfer.packets;
 
-  unsigned int packets = transfer.packets;
   if (transfer.packet_length < 0 ||
       transfer.packet_length >= kMaxPacketLength) {
     return RespondNow(Error(kErrorInvalidPacketLength));
   }
 
-  unsigned int packet_length = transfer.packet_length;
-  const uint64_t total_length = packets * packet_length;
-  if (packets > size || total_length > size) {
+  size_t total_length = packets * transfer.packet_length;
+  if (packets > size || total_length > size)
     return RespondNow(Error(kErrorTransferLength));
-  }
-
-  scoped_refptr<net::IOBuffer> buffer =
-      CreateBufferForTransfer(generic_transfer, direction, size);
-  if (!buffer.get()) {
-    return RespondNow(Error(kErrorMalformedParameters));
-  }
+  std::vector<uint32_t> packet_lengths(packets, transfer.packet_length);
 
   int timeout = generic_transfer.timeout ? *generic_transfer.timeout : 0;
-  if (timeout < 0) {
+  if (timeout < 0)
     return RespondNow(Error(kErrorInvalidTimeout));
-  }
 
-  device_handle->IsochronousTransfer(
-      direction, generic_transfer.endpoint, buffer.get(), size, packets,
-      packet_length, timeout,
-      base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  if (direction == device::USB_DIRECTION_INBOUND) {
+    device_handle->IsochronousTransferIn(
+        generic_transfer.endpoint, packet_lengths, timeout,
+        base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  } else {
+    scoped_refptr<net::IOBuffer> buffer = CreateBufferForTransfer(
+        generic_transfer, direction, transfer.packets * transfer.packet_length);
+    if (!buffer.get())
+      return RespondNow(Error(kErrorMalformedParameters));
+
+    device_handle->IsochronousTransferOut(
+        generic_transfer.endpoint, buffer.get(), packet_lengths, timeout,
+        base::Bind(&UsbIsochronousTransferFunction::OnCompleted, this));
+  }
   return RespondLater();
 }
 
+void UsbIsochronousTransferFunction::OnCompleted(
+    scoped_refptr<net::IOBuffer> data,
+    const std::vector<UsbDeviceHandle::IsochronousPacket>& packets) {
+  size_t length = std::accumulate(
+      packets.begin(), packets.end(), 0,
+      [](const size_t& a, const UsbDeviceHandle::IsochronousPacket& packet) {
+        return a + packet.transferred_length;
+      });
+  scoped_ptr<char[]> buffer(new char[length]);
+
+  UsbTransferStatus status = device::USB_TRANSFER_COMPLETED;
+  size_t buffer_offset = 0;
+  size_t data_offset = 0;
+  for (const auto& packet : packets) {
+    // Capture the error status of the first unsuccessful packet.
+    if (status == device::USB_TRANSFER_COMPLETED &&
+        packet.status != device::USB_TRANSFER_COMPLETED) {
+      status = packet.status;
+    }
+
+    memcpy(&buffer[buffer_offset], data->data() + data_offset,
+           packet.transferred_length);
+    buffer_offset += packet.transferred_length;
+    data_offset += packet.length;
+  }
+
+  scoped_ptr<base::DictionaryValue> transfer_info(new base::DictionaryValue());
+  transfer_info->SetInteger(kResultCodeKey, status);
+  transfer_info->Set(kDataKey,
+                     new base::BinaryValue(std::move(buffer), length));
+  if (status == device::USB_TRANSFER_COMPLETED) {
+    Respond(OneArgument(std::move(transfer_info)));
+  } else {
+    scoped_ptr<base::ListValue> error_args(new base::ListValue());
+    error_args->Append(std::move(transfer_info));
+    // Using ErrorWithArguments is discouraged but required to provide the
+    // detailed transfer info as the transfer may have partially succeeded.
+    Respond(ErrorWithArguments(std::move(error_args),
+                               ConvertTransferStatusToApi(status)));
+  }
+}
+
 UsbResetDeviceFunction::UsbResetDeviceFunction() {
 }
 
@@ -1210,7 +1254,8 @@ void UsbResetDeviceFunction::OnComplete(bool success) {
 
     scoped_ptr<base::ListValue> error_args(new base::ListValue());
     error_args->AppendBoolean(false);
-    // Returning arguments with an error is wrong but we're stuck with it.
+    // Using ErrorWithArguments is discouraged but required to maintain
+    // compatibility with existing applications.
     Respond(ErrorWithArguments(std::move(error_args), kErrorResetDevice));
   }
 }