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41 
42 #include "qsharedmemory.h"
43 #include "qsharedmemory_p.h"
44 
45 #include <qdebug.h>
46 
47 #ifndef QT_NO_SHAREDMEMORY
48 
49 //#define QSHAREDMEMORY_DEBUG
50 
51 QT_BEGIN_NAMESPACE
52 
QSharedMemoryPrivate()53 QSharedMemoryPrivate::QSharedMemoryPrivate()
54     : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),
55 #ifndef QT_NO_SYSTEMSEMAPHORE
56       systemSemaphore(QString()), lockedByMe(false),
57 #endif
58       hand(0)
59 {
60 }
61 
setErrorString(const QString & function)62 void QSharedMemoryPrivate::setErrorString(const QString &function)
63 {
64     DWORD windowsError = GetLastError();
65     if (windowsError == 0)
66         return;
67 
68     switch (windowsError) {
69     case ERROR_ALREADY_EXISTS:
70         error = QSharedMemory::AlreadyExists;
71         errorString = QSharedMemory::tr("%1: already exists").arg(function);
72     break;
73     case ERROR_FILE_NOT_FOUND:
74 #ifdef Q_OS_WINCE
75         // This happens on CE only if no file is present as CreateFileMappingW
76         // bails out with this error code
77     case ERROR_INVALID_PARAMETER:
78 #endif
79         error = QSharedMemory::NotFound;
80         errorString = QSharedMemory::tr("%1: doesn't exist").arg(function);
81         break;
82     case ERROR_COMMITMENT_LIMIT:
83         error = QSharedMemory::InvalidSize;
84         errorString = QSharedMemory::tr("%1: invalid size").arg(function);
85         break;
86     case ERROR_NO_SYSTEM_RESOURCES:
87     case ERROR_NOT_ENOUGH_MEMORY:
88         error = QSharedMemory::OutOfResources;
89         errorString = QSharedMemory::tr("%1: out of resources").arg(function);
90         break;
91     case ERROR_ACCESS_DENIED:
92         error = QSharedMemory::PermissionDenied;
93         errorString = QSharedMemory::tr("%1: permission denied").arg(function);
94         break;
95     default:
96         errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(windowsError);
97         error = QSharedMemory::UnknownError;
98 #ifdef QSHAREDMEMORY_DEBUG
99         qDebug() << errorString << "key" << key;
100 #endif
101         break;
102     }
103 }
104 
handle()105 HANDLE QSharedMemoryPrivate::handle()
106 {
107     if (!hand) {
108         // don't allow making handles on empty keys
109         if (nativeKey.isEmpty()) {
110             error = QSharedMemory::KeyError;
111             errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));
112             return 0;
113         }
114 #ifndef Q_OS_WINCE
115         hand = OpenFileMapping(FILE_MAP_ALL_ACCESS, false, (wchar_t*)nativeKey.utf16());
116 #else
117         // This works for opening a mapping too, but always opens it with read/write access in
118         // attach as it seems.
119         hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, 0, (wchar_t*)nativeKey.utf16());
120 #endif
121         if (!hand)
122             setErrorString(QLatin1String("QSharedMemory::handle"));
123     }
124 
125     return hand;
126 }
127 
cleanHandle()128 void QSharedMemoryPrivate::cleanHandle()
129 {
130     if (hand != 0 && !CloseHandle(hand))
131         setErrorString(QLatin1String("QSharedMemory::cleanHandle"));
132     hand = 0;
133 }
134 
create(int size)135 bool QSharedMemoryPrivate::create(int size)
136 {
137     if (nativeKey.isEmpty()) {
138         error = QSharedMemory::KeyError;
139         errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::create"));
140         return false;
141     }
142 
143     // Create the file mapping.
144     hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, size, (wchar_t*)nativeKey.utf16());
145     setErrorString(QLatin1String("QSharedMemory::create"));
146 
147     // hand is valid when it already exists unlike unix so explicitly check
148     return !(error == QSharedMemory::AlreadyExists || !hand);
149 }
150 
attach(QSharedMemory::AccessMode mode)151 bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
152 {
153     // Grab a pointer to the memory block
154     int permissions = (mode == QSharedMemory::ReadOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS);
155     memory = (void *)MapViewOfFile(handle(), permissions, 0, 0, 0);
156     if (0 == memory) {
157         setErrorString(QLatin1String("QSharedMemory::attach"));
158         cleanHandle();
159         return false;
160     }
161 
162     // Grab the size of the memory we have been given (a multiple of 4K on windows)
163     MEMORY_BASIC_INFORMATION info;
164     if (!VirtualQuery(memory, &info, sizeof(info))) {
165         // Windows doesn't set an error code on this one,
166         // it should only be a kernel memory error.
167         error = QSharedMemory::UnknownError;
168         errorString = QSharedMemory::tr("%1: size query failed").arg(QLatin1String("QSharedMemory::attach"));
169         return false;
170     }
171     size = info.RegionSize;
172 
173     return true;
174 }
175 
detach()176 bool QSharedMemoryPrivate::detach()
177 {
178     // umap memory
179     if (!UnmapViewOfFile(memory)) {
180         setErrorString(QLatin1String("QSharedMemory::detach"));
181         return false;
182     }
183     memory = 0;
184     size = 0;
185 
186     // close handle
187     cleanHandle();
188 
189     return true;
190 }
191 
192 QT_END_NAMESPACE
193 
194 #endif // QT_NO_SHAREDMEMORY
195