зеркало из https://github.com/mozilla/gecko-dev.git
Bug 1658084 - Avoid creating a mozilla::OffTheBooksMutex in a static initializer, r=emilio,mccr8
Differential Revision: https://phabricator.services.mozilla.com/D95660
This commit is contained in:
Nika Layzell
Родитель
1825576064
Коммит
188a162ad4
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@ -44,32 +44,21 @@ static bool LoadCupsFunc(PRLibrary*& lib, FuncT*& dest,
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return true;
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}
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bool nsCUPSShim::Init() {
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mozilla::OffTheBooksMutexAutoLock lock(mInitMutex);
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if (mInited) {
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return true;
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}
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nsCUPSShim::nsCUPSShim() {
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mCupsLib = PR_LoadLibrary(gCUPSLibraryName);
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if (!mCupsLib) {
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return false;
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return;
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}
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// This is a macro so that it could also load from libcups if we are configured
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// to use it as a compile-time dependency.
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// This is a macro so that it could also load from libcups if we are
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// configured to use it as a compile-time dependency.
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# define CUPS_SHIM_LOAD(NAME) \
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if (!LoadCupsFunc(mCupsLib, NAME, #NAME)) return false;
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if (!LoadCupsFunc(mCupsLib, NAME, #NAME)) return;
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CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_LOAD)
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# undef CUPS_SHIM_LOAD
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mInited = true;
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return true;
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}
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#else // CUPS_SHIM_RUNTIME_LINK
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bool nsCUPSShim::Init() {
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mInited = true;
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return true;
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// Set mInitOkay only if all cups functions are loaded successfully.
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mInitOkay = true;
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}
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#endif
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@ -18,10 +18,15 @@
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struct PRLibrary;
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/* Note: this class relies on static initialization. */
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class nsCUPSShim {
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public:
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bool EnsureInitialized() { return mInited || Init(); }
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#ifdef CUPS_SHIM_RUNTIME_LINK
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nsCUPSShim();
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bool InitOkay() { return mInitOkay; }
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#else
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nsCUPSShim() = default;
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bool InitOkay() { return true; }
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#endif
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/**
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* Function pointers for supported functions. These are only
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@ -60,7 +65,7 @@ class nsCUPSShim {
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#ifdef CUPS_SHIM_RUNTIME_LINK
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// Define a single field which holds a function pointer.
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# define CUPS_SHIM_FUNC_DECL(X) decltype(::X)* X;
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# define CUPS_SHIM_FUNC_DECL(X) decltype(::X)* X = nullptr;
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#else
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// Define a static constexpr function pointer. GCC can sometimes optimize
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// away the pointer fetch for this.
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@ -70,25 +75,10 @@ class nsCUPSShim {
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CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_FUNC_DECL)
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#undef CUPS_SHIM_FUNC_DECL
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private:
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/**
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* Initialize this object. Attempt to load the CUPS shared
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* library and find function pointers for the supported
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* functions (see below).
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* @return false if the shared library could not be loaded, or if
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* any of the functions could not be found.
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* true for successful initialization.
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*/
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bool Init();
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// We can try to get initialized from multiple threads at the same time, this
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// boolean and the mutex below make it safe.
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//
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// The boolean can't be Relaxed, because it guards our function pointers.
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mozilla::Atomic<bool, mozilla::ReleaseAcquire> mInited{false};
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#ifdef CUPS_SHIM_RUNTIME_LINK
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mozilla::OffTheBooksMutex mInitMutex{"nsCUPSShim::mInitMutex"};
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PRLibrary* mCupsLib;
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private:
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bool mInitOkay = false;
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PRLibrary* mCupsLib = nullptr;
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#endif
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};
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@ -10,7 +10,13 @@
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#include "nsString.h"
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#include "prenv.h"
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static nsCUPSShim sCupsShim;
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// Use a local static to initialize the CUPS shim lazily, when it's needed.
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// This is used in order to avoid a global constructor.
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static nsCUPSShim& CupsShim() {
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static nsCUPSShim sCupsShim;
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return sCupsShim;
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}
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using PrinterInfo = nsPrinterListBase::PrinterInfo;
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/**
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@ -23,8 +29,8 @@ static void GetDisplayNameForPrinter(const cups_dest_t& aDest,
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// while GTK clients expect non-prettified names.
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// If you change this, please change NamedPrinter accordingly.
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#ifdef XP_MACOSX
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const char* displayName =
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sCupsShim.cupsGetOption("printer-info", aDest.num_options, aDest.options);
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const char* displayName = CupsShim().cupsGetOption(
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"printer-info", aDest.num_options, aDest.options);
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if (displayName) {
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CopyUTF8toUTF16(MakeStringSpan(displayName), aName);
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}
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@ -67,7 +73,7 @@ static int CupsDestCallback(void* user_data, unsigned aFlags,
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cups_dest_t* ownedDest = nullptr;
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mozilla::DebugOnly<const int> numCopied =
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sCupsShim.cupsCopyDest(aDest, 0, &ownedDest);
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CupsShim().cupsCopyDest(aDest, 0, &ownedDest);
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MOZ_ASSERT(numCopied == 1);
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nsString name;
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@ -79,12 +85,12 @@ static int CupsDestCallback(void* user_data, unsigned aFlags,
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}
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nsTArray<PrinterInfo> nsPrinterListCUPS::Printers() const {
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if (!sCupsShim.EnsureInitialized()) {
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if (!CupsShim().InitOkay()) {
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return {};
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}
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nsTArray<PrinterInfo> printerInfoList;
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if (!sCupsShim.cupsEnumDests(
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if (!CupsShim().cupsEnumDests(
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CUPS_DEST_FLAGS_NONE,
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0 /* timeout, 0 timeout shouldn't be a problem since we are masking
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CUPS_PRINTER_DISCOVERED */
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@ -100,14 +106,14 @@ nsTArray<PrinterInfo> nsPrinterListCUPS::Printers() const {
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RefPtr<nsIPrinter> nsPrinterListCUPS::CreatePrinter(PrinterInfo aInfo) const {
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return mozilla::MakeRefPtr<nsPrinterCUPS>(
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mCommonPaperInfo, sCupsShim, std::move(aInfo.mName),
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mCommonPaperInfo, CupsShim(), std::move(aInfo.mName),
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static_cast<cups_dest_t*>(aInfo.mCupsHandle));
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}
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Maybe<PrinterInfo> nsPrinterListCUPS::PrinterByName(
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nsString aPrinterName) const {
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Maybe<PrinterInfo> rv;
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if (!sCupsShim.EnsureInitialized()) {
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if (!CupsShim().InitOkay()) {
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return rv;
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}
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@ -123,26 +129,26 @@ Maybe<PrinterInfo> nsPrinterListCUPS::PrinterByName(
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nsAutoCString printerName;
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CopyUTF16toUTF8(aPrinterName, printerName);
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cups_dest_t* printers = nullptr;
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const auto numPrinters = sCupsShim.cupsGetDests(&printers);
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const auto numPrinters = CupsShim().cupsGetDests(&printers);
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for (auto i : mozilla::IntegerRange(0, numPrinters)) {
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const char* const displayName = sCupsShim.cupsGetOption(
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const char* const displayName = CupsShim().cupsGetOption(
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"printer-info", printers[i].num_options, printers[i].options);
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if (printerName == displayName) {
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// The second arg to sCupsShim.cupsCopyDest is called num_dests, but
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// The second arg to CupsShim().cupsCopyDest is called num_dests, but
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// it actually copies num_dests + 1 elements.
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sCupsShim.cupsCopyDest(printers + i, 0, &printer);
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CupsShim().cupsCopyDest(printers + i, 0, &printer);
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break;
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}
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}
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sCupsShim.cupsFreeDests(numPrinters, printers);
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CupsShim().cupsFreeDests(numPrinters, printers);
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}
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#else
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// On GTK, we only ever show the CUPS name of printers, so we can use
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// cupsGetNamedDest directly.
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{
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const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
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printer = sCupsShim.cupsGetNamedDest(CUPS_HTTP_DEFAULT, printerName.get(),
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nullptr);
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printer = CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, printerName.get(),
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nullptr);
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}
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#endif
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@ -157,12 +163,12 @@ Maybe<PrinterInfo> nsPrinterListCUPS::PrinterByName(
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Maybe<PrinterInfo> nsPrinterListCUPS::PrinterBySystemName(
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nsString aPrinterName) const {
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Maybe<PrinterInfo> rv;
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if (!sCupsShim.EnsureInitialized()) {
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if (!CupsShim().InitOkay()) {
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return rv;
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}
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const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
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if (cups_dest_t* const printer = sCupsShim.cupsGetNamedDest(
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if (cups_dest_t* const printer = CupsShim().cupsGetNamedDest(
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CUPS_HTTP_DEFAULT, printerName.get(), nullptr)) {
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rv.emplace(PrinterInfo{std::move(aPrinterName), printer});
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}
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@ -172,14 +178,14 @@ Maybe<PrinterInfo> nsPrinterListCUPS::PrinterBySystemName(
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nsresult nsPrinterListCUPS::SystemDefaultPrinterName(nsAString& aName) const {
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aName.Truncate();
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if (!sCupsShim.EnsureInitialized()) {
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if (!CupsShim().InitOkay()) {
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return NS_ERROR_FAILURE;
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}
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// Passing in nullptr for the name will return the default, if any.
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cups_dest_t* dest =
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sCupsShim.cupsGetNamedDest(CUPS_HTTP_DEFAULT, /* name */ nullptr,
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/* instance */ nullptr);
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CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, /* name */ nullptr,
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/* instance */ nullptr);
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if (!dest) {
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return NS_OK;
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}
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@ -189,6 +195,6 @@ nsresult nsPrinterListCUPS::SystemDefaultPrinterName(nsAString& aName) const {
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CopyUTF8toUTF16(mozilla::MakeStringSpan(dest->name), aName);
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}
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sCupsShim.cupsFreeDests(1, dest);
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CupsShim().cupsFreeDests(1, dest);
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return NS_OK;
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}
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