Refactor USB vendor/product to product string to UsbUtil.h.

Also implement reading of /var/lib/usbutils/usb.ids for systems that
have it (e.g. desktop Linux).

src/UsbCameraImpl.cpp

@@ -38,6 +38,7 @@
 #include "Handle.h"
 #include "Log.h"
 #include "Notifier.h"
+#include "UsbUtil.h"
 
 using namespace cs;
 
@@ -308,10 +309,59 @@ static int SetStringCtrlIoctl(int fd, int id, int maximum,
   return DoIoctl(fd, VIDIOC_S_EXT_CTRLS, &ctrls);
 }
 
+static bool GetDescriptionSysV4L(llvm::StringRef path, std::string* desc) {
+  llvm::SmallString<64> ifpath{"/sys/class/video4linux/"};
+  ifpath += path.substr(5);
+  ifpath += "/device/interface";
+
+  int fd = open(ifpath.c_str(), O_RDONLY);
+  if (fd < 0) return false;
+
+  char readBuf[128];
+  ssize_t n = read(fd, readBuf, sizeof(readBuf));
+  close(fd);
+
+  if (n <= 0) return false;
+
+  *desc = llvm::StringRef(readBuf, n).rtrim();
+  return true;
+}
+
+static bool GetDescriptionIoctl(const char* cpath, std::string* desc) {
+  int fd = open(cpath, O_RDWR);
+  if (fd < 0) return false;
+
+  struct v4l2_capability vcap;
+  std::memset(&vcap, 0, sizeof(vcap));
+  if (DoIoctl(fd, VIDIOC_QUERYCAP, &vcap) < 0) {
+    close(fd);
+    return false;
+  }
+  close(fd);
+
+  llvm::StringRef card{reinterpret_cast<const char*>(vcap.card)};
+  // try to convert "UVC Camera (0000:0000)" into a better name
+  int vendor = 0;
+  int product = 0;
+  if (card.startswith("UVC Camera (") &&
+      !card.substr(12, 4).getAsInteger(16, vendor) &&
+      !card.substr(17, 4).getAsInteger(16, product)) {
+    llvm::SmallString<64> card2Buf;
+    llvm::StringRef card2 = GetUsbNameFromId(vendor, product, card2Buf);
+    if (!card2.empty()) {
+      *desc = card2;
+      return true;
+    }
+  }
+
+  *desc = card;
+  return true;
+}
+
 static std::string GetDescriptionImpl(const char* cpath) {
   llvm::StringRef path{cpath};
-  int fd;
   char pathBuf[128];
+  std::string rv;
 
   // If trying to get by id or path, follow symlink
   if (path.startswith("/dev/v4l/by-id/")) {
@@ -324,48 +374,11 @@ static std::string GetDescriptionImpl(const char* cpath) {
 
   if (path.startswith("/dev/video")) {
     // Sometimes the /sys tree gives a better name.
-    llvm::SmallString<64> ifpath{"/sys/class/video4linux/"};
-    ifpath += path.substr(5);
-    ifpath += "/device/interface";
-    fd = open(ifpath.c_str(), O_RDONLY);
-    if (fd >= 0) {
-      char readBuf[128];
-      ssize_t n = read(fd, readBuf, sizeof(readBuf));
-      if (n > 0) {
-        close(fd);
-        return llvm::StringRef(readBuf, n).rtrim();
-      }
-      close(fd);
-    }
+    if (GetDescriptionSysV4L(path, &rv)) return rv;
   }
 
   // Otherwise use an ioctl to query the caps and get the card name
-  fd = open(cpath, O_RDWR);
-  if (fd >= 0) {
-    struct v4l2_capability vcap;
-    std::memset(&vcap, 0, sizeof(vcap));
-    if (DoIoctl(fd, VIDIOC_QUERYCAP, &vcap) >= 0) {
-      close(fd);
-      llvm::StringRef card{reinterpret_cast<const char*>(vcap.card)};
-      // try to convert "UVC Camera (0000:0000)" into a better name
-      int vendor = 0;
-      int product = 0;
-      if (card.startswith("UVC Camera (") &&
-        !card.substr(12, 4).getAsInteger(16, vendor) &&
-        !card.substr(17, 4).getAsInteger(16, product)) {
-        switch (vendor) {
-          case 0x046d:
-            switch (product) {
-              case 0x081b: return "Logitech, Inc. Webcam C310";
-              case 0x0825: return "Logitech, Inc. Webcam C270";
-            }
-            break;
-        }
-      }
-      return card;
-    }
-    close(fd);
-  }
+  if (GetDescriptionIoctl(cpath, &rv)) return rv;
 
   return std::string{};
 }

src/UsbUtil.cpp

@@ -0,0 +1,108 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "UsbUtil.h"
+
+#include <fcntl.h>
+
+#include "llvm/Format.h"
+#include "llvm/SmallString.h"
+#include "llvm/raw_ostream.h"
+#include "support/raw_istream.h"
+
+#include "HttpUtil.h"
+
+namespace cs {
+
+static llvm::StringRef GetUsbNameFromFile(int vendor, int product,
+                                          llvm::SmallVectorImpl<char>& buf) {
+  int fd = open("/var/lib/usbutils/usb.ids", O_RDONLY);
+  if (fd < 0) return llvm::StringRef{};
+
+  llvm::raw_svector_ostream os{buf};
+  wpi::raw_fd_istream is{fd, true};
+
+  // build vendor and product 4-char hex strings
+  llvm::SmallString<16> vendorStr, productStr;
+  llvm::raw_svector_ostream vendorOs{vendorStr}, productOs{productStr};
+  vendorOs << llvm::format_hex_no_prefix(vendor, 4);
+  productOs << llvm::format_hex_no_prefix(product, 4);
+
+  // scan file
+  llvm::SmallString<128> lineBuf;
+  bool foundVendor = false;
+  for (;;) {
+    bool error = false;
+    auto line = ReadLine(is, lineBuf, 4096, &error);
+    if (error) break;
+
+    if (line.empty()) continue;
+
+    // look for vendor at start of line
+    if (line.startswith(vendorStr)) {
+      foundVendor = true;
+      os << line.substr(5).trim() << ' ';
+      continue;
+    }
+
+    if (foundVendor) {
+      // next vendor, but didn't match product?
+      if (line[0] != '\t') {
+        os << "Unknown";
+        return os.str();
+      }
+
+      // look for product
+      if (line.substr(1).startswith(productStr)) {
+        os << line.substr(6).trim();
+        return os.str();
+      }
+    }
+  }
+
+  return llvm::StringRef{};
+}
+
+llvm::StringRef GetUsbNameFromId(int vendor, int product,
+                                 llvm::SmallVectorImpl<char>& buf) {
+  // try reading usb.ids
+  llvm::StringRef rv = GetUsbNameFromFile(vendor, product, buf);
+  if (!rv.empty()) return rv;
+
+  // Fall back to internal database
+  llvm::raw_svector_ostream os{buf};
+  switch (vendor) {
+    case 0x046d:
+      os << "Logitech, Inc. ";
+      switch (product) {
+        case 0x0802: os << "Webcam C200"; break;
+        case 0x0804: os << "Webcam C250"; break;
+        case 0x0805: os << "Webcam C300"; break;
+        case 0x0807: os << "Webcam B500"; break;
+        case 0x0808: os << "Webcam C600"; break;
+        case 0x0809: os << "Webcam Pro 9000"; break;
+        case 0x080a: os << "Portable Webcam C905"; break;
+        case 0x080f: os << "Webcam C120"; break;
+        case 0x0819: os << "Webcam C210"; break;
+        case 0x081b: os << "Webcam C310"; break;
+        case 0x081d: os << "HD Webcam C510"; break;
+        case 0x0821: os << "HD Webcam C910"; break;
+        case 0x0825: os << "Webcam C270"; break;
+        case 0x0826: os << "HD Webcam C525"; break;
+        case 0x0828: os << "HD Webcam B990"; break;
+        case 0x082b: os << "Webcam C170"; break;
+        case 0x082d: os << "HD Pro Webcam C920"; break;
+        case 0x0836: os << "B525 HD Webcam"; break;
+        case 0x0843: os << "Webcam C930e"; break;
+      }
+      break;
+  }
+
+  return os.str();
+}
+
+}  // namespace cs

src/UsbUtil.h

@@ -0,0 +1,21 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef CS_USBUTIL_H_
+#define CS_USBUTIL_H_
+
+#include "llvm/SmallVector.h"
+#include "llvm/StringRef.h"
+
+namespace cs {
+
+llvm::StringRef GetUsbNameFromId(int vendor, int product,
+                                 llvm::SmallVectorImpl<char>& buf);
+
+}  // namespace cs
+
+#endif  // CS_USBUTIL_H_