Vendor import of clang trunk r135360:

http://llvm.org/svn/llvm-project/cfe/trunk@135360

1 files changed, 109 insertions, 0 deletions

diff --git a/include/clang/Basic/DelayedCleanupPool.h b/include/clang/Basic/DelayedCleanupPool.h
new file mode 100644
index 0000000..843205f
--- /dev/null
+++ b/include/clang/Basic/DelayedCleanupPool.h
@@ -0,0 +1,109 @@
+//=== DelayedCleanupPool.h - Delayed Clean-up Pool Implementation *- C++ -*===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a facility to delay calling cleanup methods until specific
+// points.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_BASIC_DELAYEDCLEANUPPOOL_H
+#define LLVM_CLANG_BASIC_DELAYEDCLEANUPPOOL_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace clang {
+
+/// \brief Gathers pairs of pointer-to-object/pointer-to-cleanup-function
+/// allowing the cleanup functions to get called (with the pointer as parameter)
+/// at specific points.
+///
+/// The use case is to simplify clean-up of certain resources that, while their
+/// lifetime is well-known and restricted, cleaning them up manually is easy to
+/// miss and cause a leak.
+///
+/// The same pointer can be added multiple times; its clean-up function will
+/// only be called once.
+class DelayedCleanupPool {
+public:
+  typedef void (*CleanupFn)(void *ptr);
+
+  /// \brief Adds a pointer and its associated cleanup function to be called
+  /// at a later point.
+  ///
+  /// \returns false if the pointer is already added, true otherwise.
+  bool delayCleanup(void *ptr, CleanupFn fn) {
+    assert(ptr && "Expected valid pointer to object");
+    assert(fn && "Expected valid pointer to function");
+
+    CleanupFn &mapFn = Ptrs[ptr];
+    assert((!mapFn || mapFn == fn) &&
+           "Adding a pointer with different cleanup function!");
+
+    if (!mapFn) {
+      mapFn = fn;
+      Cleanups.push_back(std::make_pair(ptr, fn));
+      return true;
+    }
+
+    return false;
+  }
+
+  template <typename T>
+  bool delayDelete(T *ptr) {
+    return delayCleanup(ptr, cleanupWithDelete<T>);
+  }
+
+  template <typename T, void (T::*Fn)()>
+  bool delayMemberFunc(T *ptr) {
+    return delayCleanup(ptr, cleanupWithMemberFunc<T, Fn>);
+  }
+
+  void doCleanup() {
+    for (llvm::SmallVector<std::pair<void *, CleanupFn>, 8>::reverse_iterator
+           I = Cleanups.rbegin(), E = Cleanups.rend(); I != E; ++I)
+      I->second(I->first);
+    Cleanups.clear();
+    Ptrs.clear();
+  }
+
+  ~DelayedCleanupPool() {
+    doCleanup();
+  }
+
+private:
+  llvm::DenseMap<void *, CleanupFn> Ptrs;
+  llvm::SmallVector<std::pair<void *, CleanupFn>, 8> Cleanups;
+
+  template <typename T>
+  static void cleanupWithDelete(void *ptr) {
+    delete static_cast<T *>(ptr);
+  }
+
+  template <typename T, void (T::*Fn)()>
+  static void cleanupWithMemberFunc(void *ptr) {
+    (static_cast<T *>(ptr)->*Fn)();
+  }
+};
+
+/// \brief RAII object for triggering a cleanup of a DelayedCleanupPool.
+class DelayedCleanupPoint {
+  DelayedCleanupPool &Pool;
+
+public:
+  DelayedCleanupPoint(DelayedCleanupPool &pool) : Pool(pool) { }
+
+  ~DelayedCleanupPoint() {
+    Pool.doCleanup();
+  }
+};
+
+} // end namespace clang
+
+#endif