Revert use of protobuf's Gzip streams.

Unfortunately some Red Hat-based distributions lack the required header.
See https://bugzilla.redhat.com/show_bug.cgi?id=815587

This reverts commit 261a389a76.
This reverts commit b6736eb0a5.

configure.ac

@@ -155,6 +155,8 @@ AS_IF([test x"$with_utempter" != xno],
       [AC_MSG_WARN([Unable to find libutempter; utmp entries will not be made.])],
       [AC_MSG_ERROR([--with-utempter was given but libutempter was not found.])])])])
 
+AC_SEARCH_LIBS([compress], [z], , [AC_MSG_ERROR([Unable to find zlib.])])
+
 AC_ARG_WITH([skalibs],
   [AS_HELP_STRING([--with-skalibs[=DIR]],
      [root directory of skalibs installation])],

src/network/Makefile.am

@@ -3,4 +3,4 @@ AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(PICKY_CXXFLAGS) $(HARDEN_CFLAGS) $(MISC_CXXF
 
 noinst_LIBRARIES = libmoshnetwork.a
 
-libmoshnetwork_a_SOURCES = network.cc network.h networktransport.cc networktransport.h transportfragment.cc transportfragment.h transportsender.cc transportsender.h transportstate.h
+libmoshnetwork_a_SOURCES = network.cc network.h networktransport.cc networktransport.h transportfragment.cc transportfragment.h transportsender.cc transportsender.h transportstate.h compressor.cc compressor.h

src/network/compressor.cc

@@ -0,0 +1,32 @@
+#include <zlib.h>
+
+#include "compressor.h"
+#include "dos_assert.h"
+
+using namespace Network;
+using namespace std;
+
+string Compressor::compress_str( const string &input )
+{
+  long unsigned int len = BUFFER_SIZE;
+  dos_assert( Z_OK == compress( buffer, &len,
+				reinterpret_cast<const unsigned char *>( input.data() ),
+				input.size() ) );
+  return string( reinterpret_cast<char *>( buffer ), len );
+}
+
+string Compressor::uncompress_str( const string &input )
+{
+  long unsigned int len = BUFFER_SIZE;
+  dos_assert( Z_OK == uncompress( buffer, &len,
+				  reinterpret_cast<const unsigned char *>( input.data() ),
+				  input.size() ) );
+  return string( reinterpret_cast<char *>( buffer ), len );
+}
+
+/* construct on first use */
+Compressor & Network::get_compressor( void )
+{
+  static Compressor the_compressor;
+  return the_compressor;
+}

src/network/compressor.h

@@ -0,0 +1,28 @@
+#ifndef COMPRESSOR_H
+#define COMPRESSOR_H
+
+#include <string>
+
+namespace Network {
+  class Compressor {
+  private:
+    static const int BUFFER_SIZE = 2048 * 2048; /* effective limit on terminal size */
+
+    unsigned char *buffer;
+
+  public:
+    Compressor() : buffer( NULL ) { buffer = new unsigned char[ BUFFER_SIZE ]; }
+    ~Compressor() { if ( buffer ) { delete[] buffer; } }
+
+    std::string compress_str( const std::string &input );
+    std::string uncompress_str( const std::string &input );
+
+    /* unused */
+    Compressor( const Compressor & );
+    Compressor & operator=( const Compressor & );
+  };
+
+  Compressor & get_compressor( void );
+}
+
+#endif

src/network/transportfragment.cc

@@ -17,15 +17,13 @@
 */
 
 #include <assert.h>
-#include <google/protobuf/io/gzip_stream.h>
-#include <google/protobuf/io/zero_copy_stream_impl.h>
 
 #include "byteorder.h"
 #include "transportfragment.h"
 #include "transportinstruction.pb.h"
+#include "compressor.h"
 #include "fatal_assert.h"
 
-using namespace google::protobuf::io;
 using namespace Network;
 using namespace TransportBuffers;
 
@@ -117,24 +115,15 @@ Instruction FragmentAssembly::get_assembly( void )
 {
   assert( fragments_arrived == fragments_total );
 
-  ZeroCopyInputStream **streams = new ZeroCopyInputStream *[fragments_total];
+  string encoded;
+
   for ( int i = 0; i < fragments_total; i++ ) {
     assert( fragments.at( i ).initialized );
-    streams[i] = new ArrayInputStream( fragments.at( i ).contents.data(),
+    encoded += fragments.at( i ).contents;
-				       fragments.at( i ).contents.size() );
   }
 
   Instruction ret;
-  {
+  fatal_assert( ret.ParseFromString( get_compressor().uncompress_str( encoded ) ) );
-    ConcatenatingInputStream stream( streams, fragments_total );
-    GzipInputStream gzip_stream( &stream, GzipInputStream::ZLIB );
-    fatal_assert( ret.ParseFromZeroCopyStream( &gzip_stream ) );
-  }
-
-  for ( int i = 0; i < fragments_total; i++ ) {
-    delete streams[i];
-  }
-  delete[] streams;
 
   fragments.clear();
   fragments_arrived = 0;
@@ -169,18 +158,7 @@ vector<Fragment> Fragmenter::make_fragments( const Instruction &inst, int MTU )
   last_instruction = inst;
   last_MTU = MTU;
 
-  string payload;
+  string payload = get_compressor().compress_str( inst.SerializeAsString() );
-  {
-    StringOutputStream stream( &payload );
-    GzipOutputStream::Options gzip_options;
-    gzip_options.format = GzipOutputStream::ZLIB;
-    GzipOutputStream gzip_stream( &stream, gzip_options );
-    fatal_assert( inst.SerializeToZeroCopyStream( &gzip_stream ) );
-    if ( !gzip_stream.Close() ) {
-      throw std::string( "zlib error: " ) + gzip_stream.ZlibErrorMessage();
-    }
-  }
-
   uint16_t fragment_num = 0;
   vector<Fragment> ret;