Andreas Traczyk | 45f56c9 | 2019-01-06 10:04:44 -0500 | [diff] [blame] | 1 | // From: https://stackoverflow.com/a/28172162 |
| 2 | |
| 3 | #include "runguard.h" |
| 4 | |
| 5 | #include <QCryptographicHash> |
| 6 | |
| 7 | namespace |
| 8 | { |
| 9 | |
| 10 | QString generateKeyHash(const QString& key, const QString& salt) |
| 11 | { |
| 12 | QByteArray data; |
| 13 | |
| 14 | data.append(key.toUtf8()); |
| 15 | data.append(salt.toUtf8()); |
| 16 | data = QCryptographicHash::hash(data, QCryptographicHash::Sha1).toHex(); |
| 17 | |
| 18 | return data; |
| 19 | } |
| 20 | |
| 21 | } |
| 22 | |
| 23 | RunGuard::RunGuard(const QString& key) |
| 24 | : key(key) |
| 25 | , memLockKey(generateKeyHash(key, "_memLockKey")) |
| 26 | , sharedmemKey(generateKeyHash(key, "_sharedmemKey")) |
| 27 | , sharedMem(sharedmemKey) |
| 28 | , memLock(memLockKey, 1) |
| 29 | { |
| 30 | memLock.acquire(); |
| 31 | { |
| 32 | QSharedMemory fix(sharedmemKey); // Fix for *nix: http://habrahabr.ru/post/173281/ |
| 33 | fix.attach(); |
| 34 | } |
| 35 | memLock.release(); |
| 36 | } |
| 37 | |
| 38 | RunGuard::~RunGuard() |
| 39 | { |
| 40 | release(); |
| 41 | } |
| 42 | |
| 43 | bool RunGuard::isAnotherRunning() |
| 44 | { |
| 45 | if (sharedMem.isAttached()) |
| 46 | return false; |
| 47 | |
| 48 | memLock.acquire(); |
| 49 | const bool isRunning = sharedMem.attach(); |
| 50 | if (isRunning) |
| 51 | sharedMem.detach(); |
| 52 | memLock.release(); |
| 53 | |
| 54 | return isRunning; |
| 55 | } |
| 56 | |
| 57 | bool RunGuard::tryToRun() |
| 58 | { |
| 59 | if (isAnotherRunning()) // Extra check |
| 60 | return false; |
| 61 | |
| 62 | memLock.acquire(); |
| 63 | const bool result = sharedMem.create(sizeof(quint64)); |
| 64 | memLock.release(); |
| 65 | if (!result) { |
| 66 | release(); |
| 67 | return false; |
| 68 | } |
| 69 | |
| 70 | return true; |
| 71 | } |
| 72 | |
| 73 | void RunGuard::release() |
| 74 | { |
| 75 | memLock.acquire(); |
| 76 | if (sharedMem.isAttached()) |
| 77 | sharedMem.detach(); |
| 78 | memLock.release(); |
| 79 | } |