add stream API() for webusb, add setLineStateCallback()

example work with line state callback

Author: hathach

examples/WebUSB/webusb_serial/webusb_serial.ino

@@ -20,11 +20,17 @@ Adafruit_USBD_WebUSB usb_web;
 // Landing Page: scheme (0: http, 1: https), url
 const tusb_desc_webusb_url_t landingPage = TUD_WEBUSB_URL_DESCRIPTOR(1 /*https*/, "adafruit.github.io/Adafruit_TinyUSB_Arduino/examples/webusb-serial");
 
+int led_pin = LED_BUILTIN;
+
 // the setup function runs once when you press reset or power the board
 void setup()
 {
+  pinMode(led_pin, OUTPUT);
+  digitalWrite(led_pin, LOW);
+  
   usb_web.begin();
   usb_web.setLandingPage(&landingPage);
+  usb_web.setLineStateCallback(line_state_callback);
 
   Serial.begin(115200);
 
@@ -36,6 +42,11 @@ void setup()
 
 void loop()
 {
-  delay(1000);
-  digitalWrite(LED_BUILTIN, 1-digitalRead(LED_BUILTIN));
+//  delay(1000);
+//  digitalWrite(LED_BUILTIN, 1-digitalRead(LED_BUILTIN));
+}
+
+void line_state_callback(bool connected)
+{
+  digitalWrite(led_pin, connected);
 }

src/Adafruit_USBD_WebUSB.cpp

@@ -22,6 +22,7 @@
  * THE SOFTWARE.
  */
 
+#include "Arduino.h"
 #include "Adafruit_USBD_WebUSB.h"
 
 #if CFG_TUD_VENDOR
@@ -118,6 +119,7 @@ Adafruit_USBD_WebUSB::Adafruit_USBD_WebUSB(void)
 {
   _connected = false;
   _url = NULL;
+  _linestate_cb = NULL;
 }
 
 bool Adafruit_USBD_WebUSB::begin(void)
@@ -137,6 +139,11 @@ bool Adafruit_USBD_WebUSB::setLandingPage(const void* url)
   return true;
 }
 
+void Adafruit_USBD_WebUSB::setLineStateCallback(linestate_callback_t fp)
+{
+  _linestate_cb = fp;
+}
+
 uint16_t Adafruit_USBD_WebUSB::getDescriptor(uint8_t itfnum, uint8_t* buf, uint16_t bufsize)
 {
   // usb core will automatically update endpoint number
@@ -153,24 +160,62 @@ uint16_t Adafruit_USBD_WebUSB::getDescriptor(uint8_t itfnum, uint8_t* buf, uint1
   return len;
 }
 
+bool Adafruit_USBD_WebUSB::connected(void)
+{
+  return tud_vendor_mounted() && _connected;
+}
+
+Adafruit_USBD_WebUSB::operator bool()
+{
+  // Add an yield to run usb background in case sketch block wait as follows
+  // while( !webusb ) {}
+  if ( !connected() ) yield();
+
+  return connected();
+}
+
+int Adafruit_USBD_WebUSB::available (void)
+{
+  uint32_t count = tud_vendor_available();
+
+  // Add an yield to run usb background in case sketch block wait as follows
+  // while( !webusb.available() ) {}
+  if (!count) yield();
+
+  return count;
+}
+
 int Adafruit_USBD_WebUSB::read (void)
 {
-  return -1;
+  uint8_t ch;
+  return tud_vendor_read(&ch, 1) ? (int) ch : -1;
 }
 
 size_t Adafruit_USBD_WebUSB::write (uint8_t b)
 {
-  return 0;
+  return this->write(&b, 1);
 }
 
-int Adafruit_USBD_WebUSB::available (void)
+size_t Adafruit_USBD_WebUSB::write(const uint8_t *buffer, size_t size)
 {
-  return 0;
+  size_t remain = size;
+  while ( remain && _connected )
+  {
+    size_t wrcount = tud_vendor_write(buffer, remain);
+    remain -= wrcount;
+    buffer += wrcount;
+
+    // Write FIFO is full, run usb background to flush
+    if ( remain ) yield();
+  }
+
+  return size - remain;
 }
 
 int Adafruit_USBD_WebUSB::peek (void)
 {
-  return -1;
+  uint8_t ch;
+  return tud_vendor_peek(0, &ch) ? (int) ch : -1;
 }
 
 void Adafruit_USBD_WebUSB::flush (void)
@@ -212,17 +257,13 @@ bool tud_vendor_control_request_cb(uint8_t rhport, tusb_control_request_t const
       // connect and disconnect.
       _webusb_dev->_connected = (request->wValue != 0);
 
-      // Always lit LED if connected
-      if ( request->wValue )
-      {
-
-      }else
-      {
+      // response with status OK
+      tud_control_status(rhport, request);
 
-      }
+      // invoked callback if any
+      if (_webusb_dev->_linestate_cb) _webusb_dev->_linestate_cb(_webusb_dev->_connected);
 
-      // response with status OK
-      return tud_control_status(rhport, request);
+      return true;;
 
     default:
       // stall unknown request

src/Adafruit_USBD_WebUSB.h

@@ -30,25 +30,36 @@
 class Adafruit_USBD_WebUSB : public Stream, Adafruit_USBD_Interface
 {
   public:
+    typedef void (*linestate_callback_t)(bool connected);
     Adafruit_USBD_WebUSB(void);
 
     bool begin(void);
 
     bool setLandingPage(const void* url);
+    void setLineStateCallback(linestate_callback_t fp);
 
     // Stream interface to use with MIDI Library
     virtual int    read       ( void );
-    virtual size_t write      ( uint8_t b );
     virtual int    available  ( void );
     virtual int    peek       ( void );
     virtual void   flush      ( void );
+    virtual size_t write      ( uint8_t b );
+
+    virtual size_t write(const uint8_t *buffer, size_t size);
+    size_t write(const char *buffer, size_t size) {
+      return write((const uint8_t *)buffer, size);
+    }
+
+    bool connected(void);
+    operator bool();
 
     // from Adafruit_USBD_Interface
     virtual uint16_t getDescriptor(uint8_t itfnum, uint8_t* buf, uint16_t bufsize);
 
   private:
     bool _connected;
     const uint8_t* _url;
+    linestate_callback_t _linestate_cb;
 
     // Make all tinyusb callback friend to access private data
     friend bool tud_vendor_control_request_cb(uint8_t rhport, tusb_control_request_t const * request);