1 files changed, 233 insertions, 0 deletions
diff --git a/widget/nsPrinterListCUPS.cpp b/widget/nsPrinterListCUPS.cpp
new file mode 100644
index 0000000000..2629d7626e
--- /dev/null
+++ b/widget/nsPrinterListCUPS.cpp
@@ -0,0 +1,233 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterListCUPS.h"
+
+#include "mozilla/IntegerRange.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "nsCUPSShim.h"
+#include "nsPrinterCUPS.h"
+#include "nsString.h"
+#include "prenv.h"
+
+// Use a local static to initialize the CUPS shim lazily, when it's needed.
+// This is used in order to avoid a global constructor.
+static nsCUPSShim& CupsShim() {
+  static nsCUPSShim sCupsShim;
+  return sCupsShim;
+}
+
+using PrinterInfo = nsPrinterListBase::PrinterInfo;
+
+/**
+ * Retrieves a human-readable name for the printer from CUPS.
+ * https://www.cups.org/doc/cupspm.html#basic-destination-information
+ */
+static void GetDisplayNameForPrinter(const cups_dest_t& aDest,
+                                     nsAString& aName) {
+// macOS clients expect prettified printer names
+// while GTK clients expect non-prettified names.
+// If you change this, please change NamedPrinter accordingly.
+#ifdef XP_MACOSX
+  const char* displayName = CupsShim().cupsGetOption(
+      "printer-info", aDest.num_options, aDest.options);
+  if (displayName) {
+    CopyUTF8toUTF16(mozilla::MakeStringSpan(displayName), aName);
+  }
+#endif
+}
+
+NS_IMETHODIMP
+nsPrinterListCUPS::InitPrintSettingsFromPrinter(
+    const nsAString& aPrinterName, nsIPrintSettings* aPrintSettings) {
+  MOZ_ASSERT(aPrintSettings);
+
+  // Set a default file name.
+  nsAutoString filename;
+  nsresult rv = aPrintSettings->GetToFileName(filename);
+  if (NS_FAILED(rv) || filename.IsEmpty()) {
+    const char* path = PR_GetEnv("PWD");
+    if (!path) {
+      path = PR_GetEnv("HOME");
+    }
+
+    if (path) {
+      CopyUTF8toUTF16(mozilla::MakeStringSpan(path), filename);
+      filename.AppendLiteral("/mozilla.pdf");
+    } else {
+      filename.AssignLiteral("mozilla.pdf");
+    }
+
+    aPrintSettings->SetToFileName(filename);
+  }
+
+  aPrintSettings->SetIsInitializedFromPrinter(true);
+  return NS_OK;
+}
+
+static int CupsDestCallback(void* user_data, unsigned aFlags,
+                            cups_dest_t* aDest) {
+  MOZ_ASSERT(user_data);
+  auto* printerInfoList = static_cast<nsTArray<PrinterInfo>*>(user_data);
+
+  cups_dest_t* ownedDest = nullptr;
+  mozilla::DebugOnly<const int> numCopied =
+      CupsShim().cupsCopyDest(aDest, 0, &ownedDest);
+  MOZ_ASSERT(numCopied == 1);
+
+  nsString name;
+  GetDisplayNameForPrinter(*aDest, name);
+
+  printerInfoList->AppendElement(PrinterInfo{std::move(name), ownedDest});
+
+  return aFlags == CUPS_DEST_FLAGS_MORE ? 1 : 0;
+}
+
+nsTArray<PrinterInfo> nsPrinterListCUPS::Printers() const {
+  if (!CupsShim().InitOkay()) {
+    return {};
+  }
+
+  auto FreeDestsAndClear = [](nsTArray<PrinterInfo>& aArray) {
+    for (auto& info : aArray) {
+      CupsShim().cupsFreeDests(1, static_cast<cups_dest_t*>(info.mCupsHandle));
+    }
+    aArray.Clear();
+  };
+
+  nsTArray<PrinterInfo> printerInfoList;
+  // cupsGetDests2 returns list of found printers without duplicates, unlike
+  // cupsEnumDests
+  cups_dest_t* printers = nullptr;
+  const auto numPrinters = CupsShim().cupsGetDests2(nullptr, &printers);
+  if (numPrinters > 0) {
+    for (auto i : mozilla::IntegerRange(0, numPrinters)) {
+      cups_dest_t* ownedDest = nullptr;
+      mozilla::DebugOnly<const int> numCopied =
+          CupsShim().cupsCopyDest(printers + i, 0, &ownedDest);
+      MOZ_ASSERT(numCopied == 1);
+
+      nsString name;
+      GetDisplayNameForPrinter(*(printers + i), name);
+      printerInfoList.AppendElement(PrinterInfo{std::move(name), ownedDest});
+    }
+    CupsShim().cupsFreeDests(numPrinters, printers);
+    return printerInfoList;
+  }
+
+  // An error occurred - retry with CUPS_PRINTER_DISCOVERED masked out (since
+  // it looks like there are a lot of error cases for that in cupsEnumDests):
+  if (CupsShim().cupsEnumDests(
+          CUPS_DEST_FLAGS_NONE,
+          0 /* 0 timeout should be okay when masking CUPS_PRINTER_DISCOVERED */,
+          nullptr /* cancel* */, CUPS_PRINTER_LOCAL,
+          CUPS_PRINTER_FAX | CUPS_PRINTER_SCANNER | CUPS_PRINTER_DISCOVERED,
+          &CupsDestCallback, &printerInfoList)) {
+    return printerInfoList;
+  }
+
+  // Another error occurred. Maybe printerInfoList could be partially
+  // populated, so perhaps we could return it without clearing it in the hope
+  // that there are some usable dests. However, presuambly CUPS doesn't
+  // guarantee that any dests that it added are complete and safe to use when
+  // an error occurs?
+  FreeDestsAndClear(printerInfoList);
+  return {};
+}
+
+RefPtr<nsIPrinter> nsPrinterListCUPS::CreatePrinter(PrinterInfo aInfo) const {
+  return mozilla::MakeRefPtr<nsPrinterCUPS>(
+      mCommonPaperInfo, CupsShim(), std::move(aInfo.mName),
+      static_cast<cups_dest_t*>(aInfo.mCupsHandle));
+}
+
+mozilla::Maybe<PrinterInfo> nsPrinterListCUPS::PrinterByName(
+    nsString aPrinterName) const {
+  mozilla::Maybe<PrinterInfo> rv;
+  if (!CupsShim().InitOkay()) {
+    return rv;
+  }
+
+  // Will contain the printer, if found. This must be fully owned, and not a
+  // member of another array of printers.
+  cups_dest_t* printer = nullptr;
+
+#ifdef XP_MACOSX
+  // On OS X the printer name given to this function is the readable/display
+  // name and not the CUPS name, so we iterate over all the printers for now.
+  // See bug 1659807 for one approach to improve perf here.
+  {
+    nsAutoCString printerName;
+    CopyUTF16toUTF8(aPrinterName, printerName);
+    cups_dest_t* printers = nullptr;
+    const auto numPrinters = CupsShim().cupsGetDests(&printers);
+    for (auto i : mozilla::IntegerRange(0, numPrinters)) {
+      const char* const displayName = CupsShim().cupsGetOption(
+          "printer-info", printers[i].num_options, printers[i].options);
+      if (printerName == displayName) {
+        // The second arg to CupsShim().cupsCopyDest is called num_dests, but
+        // it actually copies num_dests + 1 elements.
+        CupsShim().cupsCopyDest(printers + i, 0, &printer);
+        break;
+      }
+    }
+    CupsShim().cupsFreeDests(numPrinters, printers);
+  }
+#else
+  // On GTK, we only ever show the CUPS name of printers, so we can use
+  // cupsGetNamedDest directly.
+  {
+    const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
+    printer = CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, printerName.get(),
+                                          nullptr);
+  }
+#endif
+
+  if (printer) {
+    // Since the printer name had to be passed by-value, we can move the
+    // name from that.
+    rv.emplace(PrinterInfo{std::move(aPrinterName), printer});
+  }
+  return rv;
+}
+
+mozilla::Maybe<PrinterInfo> nsPrinterListCUPS::PrinterBySystemName(
+    nsString aPrinterName) const {
+  mozilla::Maybe<PrinterInfo> rv;
+  if (!CupsShim().InitOkay()) {
+    return rv;
+  }
+
+  const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
+  if (cups_dest_t* const printer = CupsShim().cupsGetNamedDest(
+          CUPS_HTTP_DEFAULT, printerName.get(), nullptr)) {
+    rv.emplace(PrinterInfo{std::move(aPrinterName), printer});
+  }
+  return rv;
+}
+
+nsresult nsPrinterListCUPS::SystemDefaultPrinterName(nsAString& aName) const {
+  aName.Truncate();
+
+  if (!CupsShim().InitOkay()) {
+    return NS_OK;
+  }
+
+  // Passing in nullptr for the name will return the default, if any.
+  cups_dest_t* dest =
+      CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, /* name */ nullptr,
+                                  /* instance */ nullptr);
+  if (!dest) {
+    return NS_OK;
+  }
+
+  GetDisplayNameForPrinter(*dest, aName);
+  if (aName.IsEmpty()) {
+    CopyUTF8toUTF16(mozilla::MakeStringSpan(dest->name), aName);
+  }
+
+  CupsShim().cupsFreeDests(1, dest);
+  return NS_OK;
+}