Check Qt target platform using DLL PE header

The function is64Bit() now looks into the PE header of Qt5Core.dll to
check if the target platform is 64 or 32 bit. Previously this relied on
the platform information of qmake.exe (obtained with GetBinaryType())
and so did not work for cross builds of Qt. This limitation was also
preventing the import of .pro files using a WinRT build of Qt.

Change-Id: Ib1af84c948d8bceb639601d3353482b3c92504fb
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 52 insertions, 17 deletions

diff --git a/src/qtprojectlib/VersionInformation.cs b/src/qtprojectlib/VersionInformation.cs
index fa70090f..6e520f90 100644
--- a/src/qtprojectlib/VersionInformation.cs
+++ b/src/qtprojectlib/VersionInformation.cs
@@ -201,28 +201,63 @@ namespace QtProjectLib
 
         public bool is64Bit()
         {
-            // ### This does not work for x64 cross builds of Qt.
-            // ### In that case qmake.exe is 32 bit but the DLLs are 64 bit.
-            // ### So actually we should check QtCore4.dll / QtCored4.dll instead.
-            // ### Unfortunately there's no Win API for checking the architecture of DLLs.
-            // ### We must read the PE header instead.
-            var fileToCheck = qtDir + "\\bin\\qmake.exe";
+            var fileToCheck = qtDir + "\\bin\\Qt5Core.dll";
             if (!File.Exists(fileToCheck))
                 throw new QtVSException("Can't find " + fileToCheck);
 
-            var SCS_32BIT_BINARY = 0;
-            var SCS_64BIT_BINARY = 6;
-            var binaryType = 0;
-            var success = NativeMethods.GetBinaryType(fileToCheck, ref binaryType) != 0;
-            if (!success)
-                throw new QtVSException("GetBinaryTypeA failed");
+            const ushort MAGIC_NUMBER_MZ = 0x5A4D;
+            const uint FILE_HEADER_OFFSET = 0x3C;
+            const uint PE_SIGNATURE = 0x4550;
+            const ushort IMAGE_FILE_MACHINE_I386 = 0x014c;
+            const ushort IMAGE_FILE_MACHINE_IA64 = 0x0200;
+            const ushort IMAGE_FILE_MACHINE_AMD64 = 0x8664;
 
-            if (binaryType == SCS_32BIT_BINARY)
-                return false;
-            if (binaryType == SCS_64BIT_BINARY)
-                return true;
+            using (var b = new BinaryReader(File.Open(fileToCheck,
+                FileMode.Open, FileAccess.Read, FileShare.Read))) {
 
-            throw new QtVSException("GetBinaryTypeA return unknown executable format for " + fileToCheck);
+                ushort magicNumber;
+                try {
+                    magicNumber = b.ReadUInt16();
+                } catch {
+                    throw new QtVSException("Error reading PE header: magic number");
+                }
+                if (magicNumber != MAGIC_NUMBER_MZ)
+                    throw new QtVSException("Incorrect PE header format: magic number");
+
+                uint fileHeaderOffset;
+                try {
+                    b.BaseStream.Seek(FILE_HEADER_OFFSET, SeekOrigin.Begin);
+                    fileHeaderOffset = b.ReadUInt32();
+                } catch {
+                    throw new QtVSException("Error reading PE header: file header offset");
+                }
+
+                uint signature;
+                try {
+                    b.BaseStream.Seek(fileHeaderOffset, SeekOrigin.Begin);
+                    signature = b.ReadUInt32();
+                } catch {
+                    throw new QtVSException("Error reading PE header: signature");
+                }
+                if (signature != PE_SIGNATURE)
+                    throw new QtVSException("Incorrect PE header format: signature");
+
+                ushort machine;
+                try {
+                    machine = b.ReadUInt16();
+                } catch {
+                    throw new QtVSException("Error reading PE header: machine");
+                }
+                switch (machine) {
+                    case IMAGE_FILE_MACHINE_I386:
+                        return false;
+                    case IMAGE_FILE_MACHINE_IA64:
+                    case IMAGE_FILE_MACHINE_AMD64:
+                        return true;
+                    default:
+                        throw new QtVSException("Unknown executable format for " + fileToCheck);
+                }
+            }
         }
     }
 }