VS: Compute project GUIDs deterministically

Compute deterministic GUIDs that are unique to the build tree by
hashing the path to the build tree with the GUID logical name.
Avoid storing them in the cache, but honor any found there.
This will allow project GUIDs to be reproduced in a fresh build
tree so long as its path is the same as the original, which may
be useful for incremental builds.

Source/cmGlobalGenerator.h

@@ -310,8 +310,6 @@ public:
     {
     return this->BinaryDirectories.insert(dir).second;
     }
-  /** Supported systems creates a GUID for the given name */
-  virtual void CreateGUID(const std::string&) {}
 
   /** Return true if the generated build tree may contain multiple builds.
       i.e. "Can I build Debug and Release in the same tree?" */

Source/cmGlobalVisualStudio7Generator.cxx

@@ -513,8 +513,6 @@ void cmGlobalVisualStudio7Generator::WriteTargetsToSolution(
 
             cumulativePath = cumulativePath + "/" + *iter;
             }
-
-          this->CreateGUID(cumulativePath.c_str());
           }
 
         if (!cumulativePath.empty())
@@ -899,7 +897,6 @@ cmGlobalVisualStudio7Generator::WriteUtilityDepend(cmTarget const* target)
   fname += ".vcproj";
   cmGeneratedFileStream fout(fname.c_str());
   fout.SetCopyIfDifferent(true);
-  this->CreateGUID(pname.c_str());
   std::string guid = this->GetGUID(pname.c_str());
 
   fout <<
@@ -943,41 +940,28 @@ cmGlobalVisualStudio7Generator::WriteUtilityDepend(cmTarget const* target)
   return pname;
 }
 
-std::string cmGlobalVisualStudio7Generator::GetGUID(const std::string& name)
+//----------------------------------------------------------------------------
+std::string cmGlobalVisualStudio7Generator::GetGUID(std::string const& name)
 {
-  std::string guidStoreName = name;
-  guidStoreName += "_GUID_CMAKE";
-  const char* storedGUID =
-    this->CMakeInstance->GetCacheDefinition(guidStoreName.c_str());
-  if(storedGUID)
+  std::string const& guidStoreName = name + "_GUID_CMAKE";
+  if (const char* storedGUID =
+      this->CMakeInstance->GetCacheDefinition(guidStoreName.c_str()))
     {
     return std::string(storedGUID);
     }
-  cmSystemTools::Error("Unknown Target referenced : ",
-                       name.c_str());
-  return "";
-}
-
-
-void cmGlobalVisualStudio7Generator::CreateGUID(const std::string& name)
-{
-  std::string guidStoreName = name;
-  guidStoreName += "_GUID_CMAKE";
-  if(this->CMakeInstance->GetCacheDefinition(guidStoreName.c_str()))
-    {
-    return;
-    }
-  std::string ret;
-  UUID uid;
-  unsigned short *uidstr;
-  UuidCreate(&uid);
-  UuidToStringW(&uid,&uidstr);
-  ret = cmsys::Encoding::ToNarrow(reinterpret_cast<wchar_t*>(uidstr));
-  RpcStringFreeW(&uidstr);
-  ret = cmSystemTools::UpperCase(ret);
-  this->CMakeInstance->AddCacheEntry(guidStoreName.c_str(),
-                                     ret.c_str(), "Stored GUID",
-                                     cmState::INTERNAL);
+  // Compute a GUID that is deterministic but unique to the build tree.
+  std::string input = this->CMakeInstance->GetState()->GetBinaryDirectory();
+  input += "|";
+  input += name;
+  std::string md5 = cmSystemTools::ComputeStringMD5(input);
+  assert(md5.length() == 32);
+  std::string const& guid =
+    (md5.substr( 0,8)+"-"+
+     md5.substr( 8,4)+"-"+
+     md5.substr(12,4)+"-"+
+     md5.substr(16,4)+"-"+
+     md5.substr(20,12));
+  return cmSystemTools::UpperCase(guid);
 }
 
 //----------------------------------------------------------------------------

Source/cmGlobalVisualStudio7Generator.h

@@ -80,9 +80,8 @@ public:
    */
   virtual void OutputSLNFile();
 
-  ///! Create a GUID or get an existing one.
-  void CreateGUID(const std::string& name);
-  std::string GetGUID(const std::string& name);
+  ///! Lookup a stored GUID or compute one deterministically.
+  std::string GetGUID(std::string const& name);
 
   /** Append the subdirectory for the given configuration.  */
   virtual void AppendDirectoryForConfig(const std::string& prefix,

Source/cmGlobalVisualStudio8Generator.cxx

@@ -185,7 +185,6 @@ void cmGlobalVisualStudio8Generator
 void cmGlobalVisualStudio8Generator::Configure()
 {
   this->cmGlobalVisualStudio7Generator::Configure();
-  this->CreateGUID(CMAKE_CHECK_BUILD_SYSTEM_TARGET);
 }
 
 //----------------------------------------------------------------------------

Source/cmLocalVisualStudio10Generator.cxx

@@ -107,10 +107,9 @@ void cmLocalVisualStudio10Generator
   cmVS10XMLParser parser;
   parser.ParseFile(path);
 
-  // if we can not find a GUID then create one
+  // if we can not find a GUID then we will generate one later
   if(parser.GUID.empty())
     {
-    this->GlobalGenerator->CreateGUID(name);
     return;
     }
 

Source/cmLocalVisualStudio7Generator.cxx

@@ -82,8 +82,6 @@ void cmLocalVisualStudio7Generator::AddHelperCommands()
   // Now create GUIDs for targets
   cmTargets &tgts = this->Makefile->GetTargets();
 
-  cmGlobalVisualStudio7Generator* gg =
-    static_cast<cmGlobalVisualStudio7Generator *>(this->GlobalGenerator);
   for(cmTargets::iterator l = tgts.begin(); l != tgts.end(); l++)
     {
     if(l->second.GetType() == cmTarget::INTERFACE_LIBRARY)
@@ -96,10 +94,6 @@ void cmLocalVisualStudio7Generator::AddHelperCommands()
       this->ReadAndStoreExternalGUID(
         l->second.GetName().c_str(), path);
       }
-    else
-      {
-      gg->CreateGUID(l->first.c_str());
-      }
     }
 
 
@@ -2312,12 +2306,9 @@ void cmLocalVisualStudio7Generator::ReadAndStoreExternalGUID(
 {
   cmVS7XMLParser parser;
   parser.ParseFile(path);
-  // if we can not find a GUID then create one
+  // if we can not find a GUID then we will generate one later
   if(parser.GUID.size() == 0)
     {
-    cmGlobalVisualStudio7Generator* gg =
-      static_cast<cmGlobalVisualStudio7Generator *>(this->GlobalGenerator);
-    gg->CreateGUID(name);
     return;
     }
   std::string guidStoreName = name;

Source/cmMakefile.cxx

@@ -2116,25 +2116,10 @@ void cmMakefile::AddSourceGroup(const std::vector<std::string>& name,
     return;
     }
   // build the whole source group path
-  const char* fullname = sg->GetFullName();
-  cmGlobalGenerator* gg = this->GetGlobalGenerator();
-  if(strlen(fullname))
-    {
-    std::string guidName = "SG_Filter_";
-    guidName += fullname;
-    gg->CreateGUID(guidName);
-    }
   for(++i; i<=lastElement; ++i)
     {
     sg->AddChild(cmSourceGroup(name[i].c_str(), 0, sg->GetFullName()));
     sg = sg->LookupChild(name[i].c_str());
-    fullname = sg->GetFullName();
-    if(strlen(fullname))
-      {
-      std::string guidName = "SG_Filter_";
-      guidName += fullname;
-      gg->CreateGUID(guidName);
-      }
     }
 
   sg->SetGroupRegex(regex);

Source/cmVisualStudio10TargetGenerator.cxx

@@ -178,7 +178,6 @@ cmVisualStudio10TargetGenerator(cmTarget* target,
     (cmLocalVisualStudio7Generator*)
     this->Makefile->GetLocalGenerator();
   this->Name = this->Target->GetName();
-  this->GlobalGenerator->CreateGUID(this->Name.c_str());
   this->GUID = this->GlobalGenerator->GetGUID(this->Name.c_str());
   this->Platform = gg->GetPlatformName();
   this->NsightTegra = gg->IsNsightTegra();
@@ -1084,7 +1083,6 @@ void cmVisualStudio10TargetGenerator::WriteGroups()
       (*this->BuildFileStream) << name << "\">\n";
       std::string guidName = "SG_Filter_";
       guidName += name;
-      this->GlobalGenerator->CreateGUID(guidName.c_str());
       this->WriteString("<UniqueIdentifier>", 3);
       std::string guid
         = this->GlobalGenerator->GetGUID(guidName.c_str());
@@ -1099,7 +1097,6 @@ void cmVisualStudio10TargetGenerator::WriteGroups()
     {
     this->WriteString("<Filter Include=\"Object Libraries\">\n", 2);
     std::string guidName = "SG_Filter_Object Libraries";
-    this->GlobalGenerator->CreateGUID(guidName.c_str());
     this->WriteString("<UniqueIdentifier>", 3);
     std::string guid =
       this->GlobalGenerator->GetGUID(guidName.c_str());
@@ -1112,7 +1109,6 @@ void cmVisualStudio10TargetGenerator::WriteGroups()
     {
     this->WriteString("<Filter Include=\"Resource Files\">\n", 2);
     std::string guidName = "SG_Filter_Resource Files";
-    this->GlobalGenerator->CreateGUID(guidName.c_str());
     this->WriteString("<UniqueIdentifier>", 3);
     std::string guid =
       this->GlobalGenerator->GetGUID(guidName.c_str());