102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
// Copyright 2013 Google Inc. All rights reserved.
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// Copyright 2016 the gousb Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package usb provides a wrapper around libusb-1.0.
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package usb
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type Context struct {
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ctx *libusbContext
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done chan struct{}
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}
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func (c *Context) Debug(level int) {
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libusb.setDebug(c.ctx, level)
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}
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func NewContext() *Context {
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c, err := libusb.init()
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if err != nil {
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panic(err)
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}
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ctx := &Context{
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ctx: c,
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done: make(chan struct{}),
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}
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go libusb.handleEvents(ctx.ctx, ctx.done)
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return ctx
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}
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// ListDevices calls each with each enumerated device.
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// If the function returns true, the device is opened and a Device is returned if the operation succeeds.
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// Every Device returned (whether an error is also returned or not) must be closed.
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// If there are any errors enumerating the devices,
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// the final one is returned along with any successfully opened devices.
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func (c *Context) ListDevices(each func(desc *Descriptor) bool) ([]*Device, error) {
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list, err := libusb.getDevices(c.ctx)
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if err != nil {
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return nil, err
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}
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var reterr error
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var ret []*Device
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for _, dev := range list {
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desc, err := libusb.getDeviceDesc(dev)
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if err != nil {
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libusb.dereference(dev)
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reterr = err
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continue
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}
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if each(desc) {
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handle, err := libusb.open(dev)
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if err != nil {
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reterr = err
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continue
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}
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ret = append(ret, newDevice(handle, desc))
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} else {
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libusb.dereference(dev)
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}
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}
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return ret, reterr
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}
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// OpenDeviceWithVidPid opens Device from specific VendorId and ProductId.
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// If there are any errors, it'll returns at second value.
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func (c *Context) OpenDeviceWithVidPid(vid, pid int) (*Device, error) {
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dev, handle, err := libusb.openVIDPID(c.ctx, vid, pid)
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if err != nil {
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return nil, err
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}
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desc, err := libusb.getDeviceDesc(dev)
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// return an error from nil-handle and nil-device
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if err != nil {
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libusb.dereference(dev)
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return nil, err
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}
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device := newDevice(handle, desc)
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return device, nil
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}
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func (c *Context) Close() error {
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c.done <- struct{}{}
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if c.ctx != nil {
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libusb.exit(c.ctx)
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}
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c.ctx = nil
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return nil
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}
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