ENH: add caching for the input CMakeList.txt files, 2X speed up

1 files changed, 86 insertions, 0 deletions

diff --git a/Source/cmListFileCache.cxx b/Source/cmListFileCache.cxx
new file mode 100644
index 0000000..1fade07
--- /dev/null
+++ b/Source/cmListFileCache.cxx
@@ -0,0 +1,86 @@
+#include "cmListFileCache.h"
+#include "cmSystemTools.h"
+
+
+cmListFileCache* cmListFileCache::Instance = 0;
+
+
+cmListFileCache* cmListFileCache::GetInstance()
+{
+  if(!cmListFileCache::Instance)
+    {
+    cmListFileCache::Instance = new cmListFileCache;
+    }
+  return cmListFileCache::Instance;
+}
+
+
+void cmListFileCache::ClearCache()
+{
+  delete cmListFileCache::Instance;
+  cmListFileCache::Instance = 0;
+}
+
+
+
+cmListFile* cmListFileCache::GetFileCache(const char* path)
+{
+  ListFileMap::iterator sl = m_ListFileCache.find(path);
+  if (sl == m_ListFileCache.end())
+    {
+    // if not already in the map, then parse and store the 
+    // file
+    if(!this->CacheFile(path))
+      {
+      return 0;
+      }
+    sl = m_ListFileCache.find(path);
+    if (sl == m_ListFileCache.end())
+      {
+      cmSystemTools::Error("Fatal error, in cmListFileCache CacheFile failed",
+                           path);
+      return 0;
+      }
+    }
+  cmListFile& ret = sl->second;
+  if(cmSystemTools::ModifiedTime(path) > ret.m_ModifiedTime )
+    {
+    if(!this->CacheFile(path))
+      {
+      return 0;
+      }
+    else
+      {
+      sl = m_ListFileCache.find(path);
+      return &sl->second;
+      }
+    } 
+  return &ret;
+}
+
+
+bool cmListFileCache::CacheFile(const char* path)
+{
+  std::ifstream fin(path);
+  if(!fin)
+    {
+    cmSystemTools::Error("error can not open file ", path);
+    return false;
+    }
+  std::string name;
+  std::vector<std::string> arguments;
+  cmListFile inFile;
+  inFile.m_ModifiedTime = cmSystemTools::ModifiedTime(path);
+  while ( fin )
+    {
+    cmListFileFunction inFunction;
+    if(cmSystemTools::ParseFunction(fin, 
+                                    inFunction.m_Name,
+                                    inFunction.m_Arguments))
+      {
+      inFile.m_Functions.push_back(inFunction);
+      }
+    }
+  m_ListFileCache[path] = inFile;
+  return true;
+}