Bug 1656587 - Retrieve Default Printer Name Using CUPS r=AlaskanEmily

Differential Revision: https://phabricator.services.mozilla.com/D85628

widget/CUPSPrinterList.cpp

@@ -22,7 +22,8 @@ void CUPSPrinterList::Initialize() {
 
 cups_dest_t* CUPSPrinterList::FindPrinterByName(const char* aName) {
   MOZ_ASSERT(aName);
-  return mShim.cupsGetDest(aName, NULL, mNumPrinters, mPrinters);
+  return mShim.cupsGetDest(aName, /* instance */ nullptr, mNumPrinters,
+                           mPrinters);
 }
 
 cups_dest_t* CUPSPrinterList::GetPrinter(int i) {
@@ -31,4 +32,10 @@ cups_dest_t* CUPSPrinterList::GetPrinter(int i) {
   return mPrinters + i;
 }
 
+cups_dest_t* CUPSPrinterList::GetDefaultPrinter() {
+  // Passing in nullptr for the name will return the default, if any.
+  return mShim.cupsGetNamedDest(CUPS_HTTP_DEFAULT, /* name */ nullptr,
+                                /* instance */ nullptr);
+}
+
 }  // namespace mozilla

widget/CUPSPrinterList.h

@@ -32,6 +32,7 @@ class CUPSPrinterList {
   cups_dest_t* FindPrinterByName(const char* name);
 
   int NumPrinters() const { return mNumPrinters; }
+
   /**
    * @brief Gets a printer by index.
    *
@@ -39,6 +40,13 @@ class CUPSPrinterList {
    */
   cups_dest_t* GetPrinter(int i);
 
+  /**
+   * @brief Gets the system default printer.
+   *
+   * This does NOT copy the printer's data.
+   */
+  cups_dest_t* GetDefaultPrinter();
+
  private:
   const nsCUPSShim& mShim;
   cups_dest_t* mPrinters = nullptr;

widget/cocoa/nsDeviceContextSpecX.mm

@@ -50,21 +50,53 @@ static nsCUPSShim sCupsShim;
 //----------------------------------------------------------------------
 // nsPrinterListX
 
+/**
+ * Retrieves the display name of a printer.
+ */
+static nsresult GetDisplayNameForPrinter(cups_dest_t& aDest, nsAString& aName) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
+
+  // CUPS does not appear to have a native call to retrieve a display name for
+  // a printer, so we need to use cocoa to find a display name for the printer.
+  PMPrinter corePrinter = PMPrinterCreateFromPrinterID(
+      static_cast<CFStringRef>([NSString stringWithUTF8String:aDest.name]));
+
+  if (!corePrinter) {
+    return NS_ERROR_GFX_PRINTER_NO_PRINTER_AVAILABLE;
+  }
+
+  CFStringRef printerName = PMPrinterGetName(corePrinter);
+  nsCocoaUtils::GetStringForNSString(static_cast<NSString*>(printerName), aName);
+  PMRelease(corePrinter);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
+}
+
 NS_IMPL_ISUPPORTS(nsPrinterListX, nsIPrinterList);
 
 NS_IMETHODIMP
 nsPrinterListX::GetSystemDefaultPrinterName(nsAString& aName) {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
 
-  aName.Truncate();
-  NSArray<NSString*>* printerNames = [NSPrinter printerNames];
-  if ([printerNames count] > 0) {
-    NSString* name = [printerNames objectAtIndex:0];
-    nsCocoaUtils::GetStringForNSString(name, aName);
-    return NS_OK;
+  if (!sCupsShim.IsInitialized()) {
+    if (!sCupsShim.Init()) {
+      return NS_ERROR_FAILURE;
+    }
   }
 
-  return NS_ERROR_GFX_PRINTER_NO_PRINTER_AVAILABLE;
+  mozilla::CUPSPrinterList cupsPrinterList(sCupsShim);
+  cupsPrinterList.Initialize();
+
+  cups_dest_t* const dest = cupsPrinterList.GetDefaultPrinter();
+  if (!dest) {
+    return NS_ERROR_GFX_PRINTER_NO_PRINTER_AVAILABLE;
+  }
+
+  GetDisplayNameForPrinter(*dest, aName);
+
+  return NS_OK;
 
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
@@ -79,30 +111,18 @@ nsPrinterListX::GetPrinters(nsTArray<RefPtr<nsIPrinter>>& aPrinters) {
     }
   }
 
-  mozilla::CUPSPrinterList cupsPrinterList{sCupsShim};
+  mozilla::CUPSPrinterList cupsPrinterList(sCupsShim);
   cupsPrinterList.Initialize();
   aPrinters.SetCapacity(cupsPrinterList.NumPrinters());
 
   for (int i = 0; i < cupsPrinterList.NumPrinters(); i++) {
     cups_dest_t* const dest = cupsPrinterList.GetPrinter(i);
-    RefPtr<nsPrinterCUPS> cupsPrinter = nsPrinterCUPS::Create(sCupsShim, dest);
 
-    // CUPS does not appear to have a native call to retrieve a display name for
-    // a printer, so we need to use cocoa to find a display name for the printer.
-    PMPrinter corePrinter = PMPrinterCreateFromPrinterID(
-        static_cast<CFStringRef>([NSString stringWithUTF8String:dest->name]));
-
-    if (!corePrinter) {
-      continue;
-    }
-
-    CFStringRef printerName = PMPrinterGetName(corePrinter);
-    nsAutoString displayName;
-    nsCocoaUtils::GetStringForNSString(static_cast<NSString*>(printerName), displayName);
-    cupsPrinter->SetDisplayName(displayName);
+    nsString displayName;
+    GetDisplayNameForPrinter(*dest, displayName);
+    RefPtr<nsPrinterCUPS> cupsPrinter = nsPrinterCUPS::Create(sCupsShim, dest, displayName);
 
     aPrinters.AppendElement(cupsPrinter);
-    PMRelease(corePrinter);
   }
 
   return NS_OK;

widget/nsCUPSShim.h

@@ -46,6 +46,7 @@ class nsCUPSShim {
   X(cupsGetDestMediaByIndex)   \
   X(cupsGetDest)               \
   X(cupsGetDests)              \
+  X(cupsGetNamedDest)          \
   X(cupsLocalizeDestMedia)     \
   X(cupsPrintFile)             \
   X(cupsTempFd)                \

widget/nsPrinterCUPS.cpp

@@ -9,8 +9,9 @@
 
 using namespace mozilla;
 
-nsPrinterCUPS::nsPrinterCUPS(const nsCUPSShim& aShim, cups_dest_t* aPrinter)
-    : mShim(aShim) {
+nsPrinterCUPS::nsPrinterCUPS(const nsCUPSShim& aShim, cups_dest_t* aPrinter,
+                             const nsAString& aDisplayName)
+    : mDisplayName(aDisplayName), mShim(aShim) {
   MOZ_ASSERT(aPrinter);
   MOZ_ASSERT(mShim.IsInitialized());
   DebugOnly<const int> numCopied = aShim.cupsCopyDest(aPrinter, 0, &mPrinter);
@@ -30,9 +31,10 @@ nsPrinterCUPS::~nsPrinterCUPS() {
 }
 
 // static
-already_AddRefed<nsPrinterCUPS> nsPrinterCUPS::Create(const nsCUPSShim& aShim,
-                                                      cups_dest_t* aPrinter) {
-  return do_AddRef(new nsPrinterCUPS(aShim, aPrinter));
+already_AddRefed<nsPrinterCUPS> nsPrinterCUPS::Create(
+    const nsCUPSShim& aShim, cups_dest_t* aPrinter,
+    const nsAString& aDisplayName) {
+  return do_AddRef(new nsPrinterCUPS(aShim, aPrinter, aDisplayName));
 }
 
 NS_IMETHODIMP

widget/nsPrinterCUPS.h

@@ -31,19 +31,13 @@ class nsPrinterCUPS final : public nsPrinterBase {
   /**
    * @p aPrinter must not be null.
    */
-  static already_AddRefed<nsPrinterCUPS> Create(const nsCUPSShim& aShim,
-                                                cups_dest_t* aPrinter);
-
-  /**
-   * @brief Set the display name for the printer.
-   *
-   * If a display name is not set, the PWG Standardized name will be used
-   * https://ftp.pwg.org/pub/pwg/candidates/cs-pwgmsn20-20130328-5101.1.pdf
-   */
-  void SetDisplayName(const nsAString& aName) { mDisplayName = aName; }
+  static already_AddRefed<nsPrinterCUPS> Create(
+      const nsCUPSShim& aShim, cups_dest_t* aPrinter,
+      const nsAString& aDisplayname = EmptyString());
 
  private:
-  nsPrinterCUPS(const nsCUPSShim& aShim, cups_dest_t* aPrinter);
+  nsPrinterCUPS(const nsCUPSShim& aShim, cups_dest_t* aPrinter,
+                const nsAString& aDisplayName = EmptyString());
 
   ~nsPrinterCUPS();