Bug 1687562 - Part 2: Detect whether Firefox is pinned to the taskbar. r=mhowell

Differential Revision: https://phabricator.services.mozilla.com/D105365

Author: agashlin

browser/components/shell/nsIWindowsShellService.idl

@@ -55,4 +55,18 @@ interface nsIWindowsShellService : nsISupports
    * @throws same as pinCurrentAppToTaskbar()
    */
   void checkPinCurrentAppToTaskbar();
+
+  /*
+   * Search for the current executable among taskbar pins, return true if found
+   *
+   * NOTE: This method probably shouldn't be used on the main thread, it
+   * performs blocking disk I/O.
+   *
+   * NOTE: It is possible for the check to fail even when a taskbar pin refers
+   * to this executable, if the paths differ due to e.g. symlinks.
+   * It is also possible for the check to succeed with a shortcut that doesn't
+   * actually appear on the taskbar.
+   * These cases should be rare.
+   */
+  boolean isCurrentAppPinnedToTaskbar();
 };

browser/components/shell/nsWindowsShellService.cpp

@@ -882,6 +882,98 @@ nsWindowsShellService::CheckPinCurrentAppToTaskbar() {
   return PinCurrentAppToTaskbarImpl(/* aCheckOnly */ true);
 }
 
+NS_IMETHODIMP
+nsWindowsShellService::IsCurrentAppPinnedToTaskbar(/* out */ bool* aIsPinned) {
+  *aIsPinned = false;
+
+  wchar_t exePath[MAXPATHLEN] = {};
+  if (NS_WARN_IF(NS_FAILED(BinaryPath::GetLong(exePath)))) {
+    return NS_OK;
+  }
+
+  wchar_t folderChars[MAX_PATH] = {};
+  HRESULT hr = SHGetFolderPathW(nullptr, CSIDL_APPDATA, nullptr,
+                                SHGFP_TYPE_CURRENT, folderChars);
+  if (NS_WARN_IF(FAILED(hr))) {
+    return NS_OK;
+  }
+
+  nsAutoString folder;
+  folder.Assign(folderChars);
+  if (NS_WARN_IF(folder.IsEmpty())) {
+    return NS_OK;
+  }
+  if (folder[folder.Length() - 1] != '\\') {
+    folder.AppendLiteral("\\");
+  }
+  folder.AppendLiteral(
+      "Microsoft\\Internet Explorer\\Quick Launch\\User Pinned\\TaskBar");
+  nsAutoString pattern;
+  pattern.Assign(folder);
+  pattern.AppendLiteral("\\*.lnk");
+
+  WIN32_FIND_DATAW findData = {};
+  HANDLE hFindFile = FindFirstFileW(pattern.get(), &findData);
+  if (hFindFile == INVALID_HANDLE_VALUE) {
+    Unused << NS_WARN_IF(GetLastError() != ERROR_FILE_NOT_FOUND);
+    return NS_OK;
+  }
+  // Past this point we don't return until the end of the function,
+  // when FindClose() is called.
+
+  // Check all shortcuts until a match is found
+  do {
+    nsAutoString fileName;
+    fileName.Assign(folder);
+    fileName.AppendLiteral("\\");
+    fileName.Append(findData.cFileName);
+
+    // Create a shell link object for loading the shortcut
+    RefPtr<IShellLinkW> link;
+    HRESULT hr =
+        CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_IShellLinkW, getter_AddRefs(link));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    // Load
+    RefPtr<IPersistFile> persist;
+    hr = link->QueryInterface(IID_IPersistFile, getter_AddRefs(persist));
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    hr = persist->Load(fileName.get(), STGM_READ);
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    // Note: AUMID is not checked, so a pin that does not group properly
+    // will still count as long as the exe matches.
+
+    // Check the exe path
+    static_assert(MAXPATHLEN == MAX_PATH);
+    wchar_t storedExePath[MAX_PATH] = {};
+    // With no flags GetPath gets a long path
+    hr = link->GetPath(storedExePath, ArrayLength(storedExePath), nullptr, 0);
+    if (FAILED(hr) || hr == S_FALSE) {
+      continue;
+    }
+    // Case insensitive path comparison
+    // NOTE: Because this compares the path directly, it is possible to
+    // have a false negative mismatch.
+    if (wcsnicmp(storedExePath, exePath, MAXPATHLEN) == 0) {
+      *aIsPinned = true;
+      break;
+    }
+  } while (FindNextFileW(hFindFile, &findData));
+
+  FindClose(hFindFile);
+
+  return NS_OK;
+}
+
 nsWindowsShellService::nsWindowsShellService() {}
 
 nsWindowsShellService::~nsWindowsShellService() {}