ENH: Refactor custom command rule hashing

This simplifies computation of custom command rule hashes to hash
content exactly chosen as the custom commands are generated.
Unfortunately this will change the hashes of existing build trees from
earlier CMake versions, but this is not a big deal.  The change is
necessary so that in the future we can make optional adjustments to
custom command lines at generate time without changing the hashes every
time the option is changed.

5 files changed, 23 insertions, 20 deletions

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index be9b0df..b0a6e83 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -2004,8 +2004,7 @@ cmGlobalGenerator::GetDirectoryContent(std::string const& dir, bool needDisk)
 //----------------------------------------------------------------------------
 void
 cmGlobalGenerator::AddRuleHash(const std::vector<std::string>& outputs,
-                               std::vector<std::string>::const_iterator first,
-                               std::vector<std::string>::const_iterator last)
+                               std::string const& content)
 {
 #if defined(CMAKE_BUILD_WITH_CMAKE)
   // Ignore if there are no outputs.
@@ -2017,16 +2016,12 @@ cmGlobalGenerator::AddRuleHash(const std::vector<std::string>& outputs,
   // Compute a hash of the rule.
   RuleHash hash;
   {
-  unsigned char const* data;
-  int length;
+  unsigned char const* data =
+    reinterpret_cast<unsigned char const*>(content.c_str());
+  int length = static_cast<int>(content.length());
   cmsysMD5* sum = cmsysMD5_New();
   cmsysMD5_Initialize(sum);
-  for(std::vector<std::string>::const_iterator i = first; i != last; ++i)
-    {
-    data = reinterpret_cast<unsigned char const*>(i->c_str());
-    length = static_cast<int>(i->length());
-    cmsysMD5_Append(sum, data, length);
-    }
+  cmsysMD5_Append(sum, data, length);
   cmsysMD5_FinalizeHex(sum, hash.Data);
   cmsysMD5_Delete(sum);
   }
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index 51e462d..60847c2 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -251,8 +251,7 @@ public:
   void GetFilesReplacedDuringGenerate(std::vector<std::string>& filenames);
 
   void AddRuleHash(const std::vector<std::string>& outputs,
-                   std::vector<std::string>::const_iterator first,
-                   std::vector<std::string>::const_iterator last);
+                   std::string const& content);
 
 protected:
   // for a project collect all its targets by following depend
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index 9517cd8..fad722d 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -968,7 +968,8 @@ void
 cmLocalUnixMakefileGenerator3
 ::AppendCustomCommand(std::vector<std::string>& commands,
                       const cmCustomCommand& cc, bool echo_comment,
-                      cmLocalGenerator::RelativeRoot relative)
+                      cmLocalGenerator::RelativeRoot relative,
+                      std::ostream* content)
 {
   // Optionally create a command to display the custom command's
   // comment text.  This is used for pre-build, pre-link, and
@@ -991,6 +992,10 @@ cmLocalUnixMakefileGenerator3
     {
     dir = workingDir;
     }
+  if(content)
+    {
+    *content << dir;
+    }
   bool escapeOldStyle = cc.GetEscapeOldStyle();
   bool escapeAllowMakeVars = cc.GetEscapeAllowMakeVars();
 
@@ -1048,6 +1053,10 @@ cmLocalUnixMakefileGenerator3
                                       escapeAllowMakeVars);
           }
         }
+      if(content)
+        {
+        *content << cmd;
+        }
       if(this->BorlandMakeCurlyHack)
         {
         // Borland Make has a very strange bug.  If the first curly
diff --git a/Source/cmLocalUnixMakefileGenerator3.h b/Source/cmLocalUnixMakefileGenerator3.h
index ebb7c79..b35bdbc 100644
--- a/Source/cmLocalUnixMakefileGenerator3.h
+++ b/Source/cmLocalUnixMakefileGenerator3.h
@@ -332,7 +332,8 @@ protected:
                            const cmCustomCommand& cc,
                            bool echo_comment=false,
                            cmLocalGenerator::RelativeRoot relative =
-                           cmLocalGenerator::HOME_OUTPUT);
+                           cmLocalGenerator::HOME_OUTPUT,
+                           std::ostream* content = 0);
   void AppendCleanCommand(std::vector<std::string>& commands,
                           const std::vector<std::string>& files,
                           cmTarget& target, const char* filename =0);
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index e19cd1d..c2cad66 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -1119,11 +1119,12 @@ void cmMakefileTargetGenerator
       ->AppendEcho(commands, comment.c_str(),
                    cmLocalUnixMakefileGenerator3::EchoGenerate);
     }
-  // Below we need to skip over the echo and progress commands.
-  unsigned int skip = static_cast<unsigned int>(commands.size());
 
   // Now append the actual user-specified commands.
-  this->LocalGenerator->AppendCustomCommand(commands, cc);
+  cmOStringStream content;
+  this->LocalGenerator->AppendCustomCommand(commands, cc, false,
+                                            cmLocalGenerator::HOME_OUTPUT,
+                                            &content);
 
   // Collect the dependencies.
   std::vector<std::string> depends;
@@ -1151,9 +1152,7 @@ void cmMakefileTargetGenerator
   // If the rule has changed make sure the output is rebuilt.
   if(!symbolic)
     {
-    this->GlobalGenerator->AddRuleHash(cc.GetOutputs(),
-                                       commands.begin()+skip,
-                                       commands.end());
+    this->GlobalGenerator->AddRuleHash(cc.GetOutputs(), content.str());
     }
   }