1 files changed, 78 insertions, 0 deletions
diff --git a/Source/cmFileLockUnix.cxx b/Source/cmFileLockUnix.cxx
new file mode 100644
index 0000000..7353b01
--- /dev/null
+++ b/Source/cmFileLockUnix.cxx
@@ -0,0 +1,78 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmFileLock.h"
+
+#include "cmSystemTools.h"
+#include <errno.h> // errno
+#include <fcntl.h>
+#include <stdio.h> // SEEK_SET
+#include <unistd.h>
+
+cmFileLock::cmFileLock()
+  : File(-1)
+{
+}
+
+cmFileLockResult cmFileLock::Release()
+{
+  if (this->Filename.empty()) {
+    return cmFileLockResult::MakeOk();
+  }
+  const int lockResult = this->LockFile(F_SETLK, F_UNLCK);
+
+  this->Filename = "";
+
+  ::close(this->File);
+  this->File = -1;
+
+  if (lockResult == 0) {
+    return cmFileLockResult::MakeOk();
+  }
+  return cmFileLockResult::MakeSystem();
+}
+
+cmFileLockResult cmFileLock::OpenFile()
+{
+  this->File = ::open(this->Filename.c_str(), O_RDWR);
+  if (this->File == -1) {
+    return cmFileLockResult::MakeSystem();
+  }
+  return cmFileLockResult::MakeOk();
+}
+
+cmFileLockResult cmFileLock::LockWithoutTimeout()
+{
+  if (this->LockFile(F_SETLKW, F_WRLCK) == -1) {
+    return cmFileLockResult::MakeSystem();
+  }
+  return cmFileLockResult::MakeOk();
+}
+
+cmFileLockResult cmFileLock::LockWithTimeout(unsigned long seconds)
+{
+  while (true) {
+    if (this->LockFile(F_SETLK, F_WRLCK) == -1) {
+      if (errno != EACCES && errno != EAGAIN) {
+        return cmFileLockResult::MakeSystem();
+      }
+    } else {
+      return cmFileLockResult::MakeOk();
+    }
+    if (seconds == 0) {
+      return cmFileLockResult::MakeTimeout();
+    }
+    --seconds;
+    cmSystemTools::Delay(1000);
+  }
+}
+
+int cmFileLock::LockFile(int cmd, int type)
+{
+  struct ::flock lock;
+  lock.l_start = 0;
+  lock.l_len = 0;                         // lock all bytes
+  lock.l_pid = 0;                         // unused (for F_GETLK only)
+  lock.l_type = static_cast<short>(type); // exclusive lock
+  lock.l_whence = SEEK_SET;
+  return ::fcntl(this->File, cmd, &lock);
+}