1 files changed, 87 insertions, 0 deletions
diff --git a/Source/cmVariableWatch.cxx b/Source/cmVariableWatch.cxx
new file mode 100644
index 0000000..3df1420
--- /dev/null
+++ b/Source/cmVariableWatch.cxx
@@ -0,0 +1,87 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmVariableWatch.h"
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+static const char* const cmVariableWatchAccessStrings[] = {
+  "READ_ACCESS",     "UNKNOWN_READ_ACCESS", "UNKNOWN_DEFINED_ACCESS",
+  "MODIFIED_ACCESS", "REMOVED_ACCESS",      "NO_ACCESS"
+};
+
+const char* cmVariableWatch::GetAccessAsString(int access_type)
+{
+  if (access_type < 0 || access_type >= cmVariableWatch::NO_ACCESS) {
+    return "NO_ACCESS";
+  }
+  return cmVariableWatchAccessStrings[access_type];
+}
+
+cmVariableWatch::cmVariableWatch() = default;
+
+cmVariableWatch::~cmVariableWatch() = default;
+
+bool cmVariableWatch::AddWatch(const std::string& variable, WatchMethod method,
+                               void* client_data /*=0*/,
+                               DeleteData delete_data /*=0*/)
+{
+  auto p = std::make_shared<cmVariableWatch::Pair>();
+  p->Method = method;
+  p->ClientData = client_data;
+  p->DeleteDataCall = delete_data;
+  cmVariableWatch::VectorOfPairs& vp = this->WatchMap[variable];
+  for (auto& pair : vp) {
+    if (pair->Method == method && client_data &&
+        client_data == pair->ClientData) {
+      // Callback already exists
+      return false;
+    }
+  }
+  vp.push_back(std::move(p));
+  return true;
+}
+
+void cmVariableWatch::RemoveWatch(const std::string& variable,
+                                  WatchMethod method, void* client_data /*=0*/)
+{
+  if (!this->WatchMap.count(variable)) {
+    return;
+  }
+  cmVariableWatch::VectorOfPairs* vp = &this->WatchMap[variable];
+  cmVariableWatch::VectorOfPairs::iterator it;
+  for (it = vp->begin(); it != vp->end(); ++it) {
+    if ((*it)->Method == method &&
+        // If client_data is NULL, we want to disconnect all watches against
+        // the given method; otherwise match ClientData as well.
+        (!client_data || (client_data == (*it)->ClientData))) {
+      vp->erase(it);
+      return;
+    }
+  }
+}
+
+bool cmVariableWatch::VariableAccessed(const std::string& variable,
+                                       int access_type, const char* newValue,
+                                       const cmMakefile* mf) const
+{
+  cmVariableWatch::StringToVectorOfPairs::const_iterator mit =
+    this->WatchMap.find(variable);
+  if (mit != this->WatchMap.end()) {
+    // The strategy here is to copy the list of callbacks, and ignore
+    // new callbacks that existing ones may add.
+    std::vector<std::weak_ptr<Pair>> vp(mit->second.begin(),
+                                        mit->second.end());
+    for (auto& weak_it : vp) {
+      // In the case where a callback was removed, the weak_ptr will not be
+      // lockable, and so this ensures we don't attempt to call into freed
+      // memory
+      if (auto it = weak_it.lock()) {
+        it->Method(variable, access_type, it->ClientData, newValue, mf);
+      }
+    }
+    return true;
+  }
+  return false;
+}