Changeset 72013 in vbox

Timestamp:

Apr 25, 2018 1:19:33 PM (7 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

122274

Message:

UIDesktopWidgetWatchdog.cpp: Resolve GetDpiForMonitor too, and don't bother with MonitorEnumProcF unless its there. Go thru RTLdrGetSystemSymbol rather that QLibrary, as the former is known to always be secure wrt PATH searching and such. Don't dynamically import EnumDisplayMonitors.

File:

• trunk/src/VBox/Frontends/VirtualBox/src/globals/UIDesktopWidgetWatchdog.cpp (modified) (5 diffs)

trunk/src/VBox/Frontends/VirtualBox/src/globals/UIDesktopWidgetWatchdog.cpp

@@ -38 +38 @@
 
 /* Other VBox includes: */
+# include <iprt/asm.h>
 # include <iprt/assert.h>
+# include <iprt/ldr.h>
 # include <VBox/log.h>
 
@@ -51 +53 @@
 #ifdef VBOX_WS_WIN
 
+# ifndef DPI_ENUMS_DECLARED
 typedef enum _MONITOR_DPI_TYPE // gently stolen from MSDN
 {
@@ -58 +61 @@
     MDT_DEFAULT        = MDT_EFFECTIVE_DPI
 } MONITOR_DPI_TYPE;
+# endif
+typedef void (WINAPI *PFN_GetDpiForMonitor)(HMONITOR, MONITOR_DPI_TYPE, uint *, uint *);
+
+/** Set when dynamic API import is reoslved. */
+static bool volatile        g_fResolved;
+/** Pointer to Shcore.dll!GetDpiForMonitor, introduced in windows 8.1. */
+static PFN_GetDpiForMonitor g_pfnGetDpiForMonitor = NULL;
+
+/** @returns true if all APIs found, false if missing APIs  */
+static bool ResolveDynamicImports(void)
+{
+    if (!g_fResolved)
+    {
+        PFN_GetDpiForMonitor pfn = (decltype(pfn))RTLdrGetSystemSymbol("Shcore.dll", "GetDpiForMonitor");
+        g_pfnGetDpiForMonitor = pfn;
+        ASMCompilerBarrier();
+
+        g_fResolved = true;
+    }
+    return g_pfnGetDpiForMonitor != NULL;
+}
 
 static BOOL CALLBACK MonitorEnumProcF(HMONITOR hMonitor, HDC hdcMonitor, LPRECT lpClipRect, LPARAM dwData)
@@ -64 +88 @@
     RT_NOREF(hdcMonitor, lpClipRect);
 
-    /* Dynamically access Shcore.dll: */
-    QLibrary shcore("Shcore.dll", NULL);
-
     /* Acquire effective DPI (available since Windows 8.1): */
-    typedef void (WINAPI *GetDpiForMonitorFP)(HMONITOR hMonitor, MONITOR_DPI_TYPE enmDpiType, uint *puOutX, uint *puOutY);
-    GetDpiForMonitorFP GetDpiForMonitorF = (GetDpiForMonitorFP)shcore.resolve("GetDpiForMonitor");
-    if (GetDpiForMonitorF)
-    {
-        uint uOutX = 0;
-        uint uOutY = 0;
-        GetDpiForMonitorF(hMonitor, MDT_EFFECTIVE_DPI, &uOutX, &uOutY);
-        reinterpret_cast<QList<QPair<int, int> >*>(dwData)->append(qMakePair(uOutX, uOutY));
-        return true;
-    }
-
-    /* False by default: */
-    return false;
+    AssertReturn(g_pfnGetDpiForMonitor, false);
+    uint uOutX = 0;
+    uint uOutY = 0;
+    g_pfnGetDpiForMonitor(hMonitor, MDT_EFFECTIVE_DPI, &uOutX, &uOutY);
+    reinterpret_cast<QList<QPair<int, int> >*>(dwData)->append(qMakePair(uOutX, uOutY));
+
+    return TRUE;
 }
 
@@ -432 +447 @@
 
 #ifdef VBOX_WS_WIN
-    /* Dynamically resolve EnumDisplayMonitors (available since Windows 2k) first time through: */
-    static bool volatile                  s_fResolved = false;
-    static decltype(EnumDisplayMonitors) *s_pfnEnumDisplayMonitors = NULL;
-    decltype(EnumDisplayMonitors)        *pfnEnumDisplayMonitors;
-    if (s_fResolved)
-        pfnEnumDisplayMonitors = s_pfnEnumDisplayMonitors;
-    else
-    {
-        pfnEnumDisplayMonitors = (decltype(EnumDisplayMonitors) *)GetProcAddress(GetModuleHandleW(L"USER32.DLL"),
-                                                                                 "EnumDisplayMonitors");
-        s_pfnEnumDisplayMonitors = pfnEnumDisplayMonitors;
-        s_fResolved = true;
-    }
-
-    /* Enumerate available monitors through EnumDisplayMonitors if available: */
-    if (pfnEnumDisplayMonitors)
+    /* Enumerate available monitors through EnumDisplayMonitors if GetDpiForMonitor is available: */
+    if (ResolveDynamicImports())
     {
         QList<QPair<int, int> > listOfScreenDPI;
-        pfnEnumDisplayMonitors(0, 0, MonitorEnumProcF, (LPARAM)&listOfScreenDPI);
+        EnumDisplayMonitors(0, 0, MonitorEnumProcF, (LPARAM)&listOfScreenDPI);
         if (iHostScreenIndex >= 0 && iHostScreenIndex < listOfScreenDPI.size())
         {