file: Add LOCK subcommand to do file and directory locking

Provide options to fail without blocking or to block up to a timeout.
Provide options to specify the scope containing the lock so it can be
released automatically at the end of a function, file, or process.

Extend the RunCMake.file test with cases covering the file(LOCK) command
usage and error cases.

Source/cmFileLockPool.cxx

@@ -0,0 +1,198 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2014 Ruslan Baratov
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+
+#include "cmFileLockPool.h"
+
+#include <assert.h>
+
+#include "cmFileLock.h"
+#include "cmFileLockResult.h"
+
+cmFileLockPool::cmFileLockPool()
+{
+}
+
+cmFileLockPool::~cmFileLockPool()
+{
+  for (It i = this->FunctionScopes.begin();
+      i != this->FunctionScopes.end(); ++i)
+    {
+    delete *i;
+    }
+
+  for (It i = this->FileScopes.begin(); i != this->FileScopes.end(); ++i)
+    {
+    delete *i;
+    }
+}
+
+void cmFileLockPool::PushFunctionScope()
+{
+  this->FunctionScopes.push_back(new ScopePool());
+}
+
+void cmFileLockPool::PopFunctionScope()
+{
+  assert(!this->FunctionScopes.empty());
+  delete this->FunctionScopes.back();
+  this->FunctionScopes.pop_back();
+}
+
+void cmFileLockPool::PushFileScope()
+{
+  this->FileScopes.push_back(new ScopePool());
+}
+
+void cmFileLockPool::PopFileScope()
+{
+  assert(!this->FileScopes.empty());
+  delete this->FileScopes.back();
+  this->FileScopes.pop_back();
+}
+
+cmFileLockResult cmFileLockPool::LockFunctionScope(
+    const std::string& filename, unsigned timeoutSec)
+{
+  if (this->IsAlreadyLocked(filename))
+    {
+    return cmFileLockResult::MakeAlreadyLocked();
+    }
+  if (this->FunctionScopes.empty())
+    {
+    return cmFileLockResult::MakeNoFunction();
+    }
+  return this->FunctionScopes.back()->Lock(filename, timeoutSec);
+}
+
+cmFileLockResult cmFileLockPool::LockFileScope(
+    const std::string& filename, unsigned timeoutSec)
+{
+  if (this->IsAlreadyLocked(filename))
+    {
+    return cmFileLockResult::MakeAlreadyLocked();
+    }
+  assert(!this->FileScopes.empty());
+  return this->FileScopes.back()->Lock(filename, timeoutSec);
+}
+
+cmFileLockResult cmFileLockPool::LockProcessScope(
+    const std::string& filename, unsigned timeoutSec)
+{
+  if (this->IsAlreadyLocked(filename))
+    {
+    return cmFileLockResult::MakeAlreadyLocked();
+    }
+  return this->ProcessScope.Lock(filename, timeoutSec);
+}
+
+cmFileLockResult cmFileLockPool::Release(const std::string& filename)
+{
+  for (It i = this->FunctionScopes.begin();
+      i != this->FunctionScopes.end(); ++i)
+    {
+    const cmFileLockResult result = (*i)->Release(filename);
+    if (!result.IsOk())
+      {
+      return result;
+      }
+    }
+
+  for (It i = this->FileScopes.begin(); i != this->FileScopes.end(); ++i)
+    {
+    const cmFileLockResult result = (*i)->Release(filename);
+    if (!result.IsOk())
+      {
+      return result;
+      }
+    }
+
+  return this->ProcessScope.Release(filename);
+}
+
+bool cmFileLockPool::IsAlreadyLocked(const std::string& filename) const
+{
+  for (CIt i = this->FunctionScopes.begin();
+      i != this->FunctionScopes.end(); ++i)
+    {
+    const bool result = (*i)->IsAlreadyLocked(filename);
+    if (result)
+      {
+      return true;
+      }
+    }
+
+  for (CIt i = this->FileScopes.begin(); i != this->FileScopes.end(); ++i)
+    {
+    const bool result = (*i)->IsAlreadyLocked(filename);
+    if (result)
+      {
+      return true;
+      }
+    }
+
+  return this->ProcessScope.IsAlreadyLocked(filename);
+}
+
+cmFileLockPool::ScopePool::ScopePool()
+{
+}
+
+cmFileLockPool::ScopePool::~ScopePool()
+{
+  for (It i = this->Locks.begin(); i != this->Locks.end(); ++i)
+    {
+    delete *i;
+    }
+}
+
+cmFileLockResult cmFileLockPool::ScopePool::Lock(
+    const std::string& filename, unsigned timeoutSec)
+{
+  cmFileLock *lock = new cmFileLock();
+  const cmFileLockResult result = lock->Lock(filename, timeoutSec);
+  if (result.IsOk())
+    {
+    this->Locks.push_back(lock);
+    return cmFileLockResult::MakeOk();
+    }
+  else
+    {
+    delete lock;
+    return result;
+    }
+}
+
+cmFileLockResult cmFileLockPool::ScopePool::Release(
+    const std::string& filename)
+{
+  for (It i = this->Locks.begin(); i != this->Locks.end(); ++i)
+    {
+    if ((*i)->IsLocked(filename))
+      {
+      return (*i)->Release();
+      }
+    }
+  return cmFileLockResult::MakeOk();
+}
+
+bool cmFileLockPool::ScopePool::IsAlreadyLocked(
+    const std::string& filename) const
+{
+  for (CIt i = this->Locks.begin(); i != this->Locks.end(); ++i)
+    {
+    if ((*i)->IsLocked(filename))
+      {
+      return true;
+      }
+    }
+  return false;
+}