Preserve composite-data names in legacy readers/writers.

vtkCompositeDataWriter/vtkCompositeDataReader didn't preserve composite data
block names. Fixed that.

Change-Id: Iad7c950bab05064f617e881f09cd7ff179398673

IO/Legacy/vtkCompositeDataReader.cxx

@@ -31,6 +31,7 @@
 #include "vtkStreamingDemandDrivenPipeline.h"
 #include "vtkUniformGrid.h"
 
+#include <vtksys/RegularExpression.hxx>
 #include <vtksys/SystemTools.hxx>
 #include <vtksys/ios/sstream>
 
@@ -279,6 +280,13 @@ bool vtkCompositeDataReader::ReadCompositeData(vtkMultiBlockDataSet* mb)
       }
     // eat up the "\n" and other whitespace at the end of CHILD <type>.
     this->ReadLine(line);
+    // if "line" has text enclosed in [] then that's the composite name.
+    vtksys::RegularExpression regEx("\\s*\\[(.*)\\]");
+    if (regEx.find(line))
+      {
+      std::string name = regEx.match(1);
+      mb->GetMetaData(cc)->Set(vtkCompositeDataSet::NAME(), name.c_str());
+      }
 
     if (type != -1)
       {
@@ -526,6 +534,13 @@ bool vtkCompositeDataReader::ReadCompositeData(vtkMultiPieceDataSet* mp)
       }
     // eat up the "\n" and other whitespace at the end of CHILD <type>.
     this->ReadLine(line);
+    // if "line" has text enclosed in [] then that's the composite name.
+    vtksys::RegularExpression regEx("\\s*\\[(.*)\\]");
+    if (regEx.find(line))
+      {
+      std::string name = regEx.match(1);
+      mp->GetMetaData(cc)->Set(vtkCompositeDataSet::NAME(), name.c_str());
+      }
 
     if (type != -1)
       {

IO/Legacy/vtkCompositeDataWriter.cxx

@@ -154,7 +154,15 @@ bool vtkCompositeDataWriter::WriteCompositeData(ostream* fp,
   for (unsigned int cc=0; cc < mb->GetNumberOfBlocks(); cc++)
     {
     vtkDataObject* child = mb->GetBlock(cc);
-    *fp << "CHILD " << (child? child->GetDataObjectType() : -1) << "\n";
+    *fp << "CHILD " << (child? child->GetDataObjectType() : -1);
+    // add name if present.
+    if (mb->HasMetaData(cc) &&
+      mb->GetMetaData(cc)->Has(vtkCompositeDataSet::NAME()))
+      {
+      *fp << " [" << mb->GetMetaData(cc)->Get(vtkCompositeDataSet::NAME())
+          << "]";
+      }
+    *fp << "\n";
     if (child)
       {
       if (!this->WriteBlock(fp, child))
@@ -176,7 +184,16 @@ bool vtkCompositeDataWriter::WriteCompositeData(ostream* fp,
   for (unsigned int cc=0; cc < mp->GetNumberOfPieces(); cc++)
     {
     vtkDataObject* child = mp->GetPieceAsDataObject(cc);
-    *fp << "CHILD " << (child? child->GetDataObjectType() : -1) << "\n";
+    *fp << "CHILD " << (child? child->GetDataObjectType() : -1);
+    // add name if present.
+    if (mp->HasMetaData(cc) &&
+      mp->GetMetaData(cc)->Has(vtkCompositeDataSet::NAME()))
+      {
+      *fp << " [" << mp->GetMetaData(cc)->Get(vtkCompositeDataSet::NAME())
+          << "]";
+      }
+    *fp << "\n";
+
     if (child)
       {
       if (!this->WriteBlock(fp, child))