ENH: Added computation of object file names that are almost always short enough to not exceed the filesystem path length limitation. This is useful when a source file from outside the tree is referenced with a long full path. The object file name previously would contain the entire path which when combined with the build output directory could exceed the filesystem limit. Now CMake recognizes this case and replaces enough of the beginning of the full path to the source file with an md5sum of the replaced portion to make the name fit on disk. This addresses bug#4520.

1 files changed, 27 insertions, 2 deletions

diff --git a/Source/cmLocalVisualStudio6Generator.cxx b/Source/cmLocalVisualStudio6Generator.cxx
index 6a24b01..3a72de6 100644
--- a/Source/cmLocalVisualStudio6Generator.cxx
+++ b/Source/cmLocalVisualStudio6Generator.cxx
@@ -397,7 +397,32 @@ void cmLocalVisualStudio6Generator
     {
     this->WriteDSPBeginGroup(fout, name.c_str(), "");
     }
-    
+
+  // Compute the maximum length of a configuration name.
+  std::string::size_type config_len_max = 0;
+  for(std::vector<std::string>::iterator i = this->Configurations.begin();
+      i != this->Configurations.end(); ++i)
+    {
+    // Strip the subdirectory name out of the configuration name.
+    std::string config = *i;
+    std::string::size_type pos = config.find_last_of(" ");
+    config = config.substr(pos+1, std::string::npos);
+    config = config.substr(0, config.size()-1);
+    if(config.size() > config_len_max)
+      {
+      config_len_max = config.size();
+      }
+    }
+
+  // Compute the maximum length of the full path to the intermediate
+  // files directory for any configuration.  This is used to construct
+  // object file names that do not produce paths that are too long.
+  std::string::size_type dir_len = 0;
+  dir_len += strlen(this->Makefile->GetCurrentOutputDirectory());
+  dir_len += 1;
+  dir_len += config_len_max;
+  dir_len += 1;
+
   // Loop through each source in the source group.
   for(std::vector<const cmSourceFile *>::const_iterator sf =
         sourceFiles.begin(); sf != sourceFiles.end(); ++sf)
@@ -412,7 +437,7 @@ void cmLocalVisualStudio6Generator
       {
       objectNameDir =
         cmSystemTools::GetFilenamePath(
-          this->GetObjectFileNameWithoutTarget(*(*sf)));
+          this->GetObjectFileNameWithoutTarget(*(*sf), dir_len));
       }
 
     // Add per-source file flags.