prepare lzo support for pull request - 2nd half

- move compression_method field from BundleInfo to file header
- add a test case to make sure this doesn't break compatibility

bundle.cc

@@ -33,12 +33,11 @@ void Creator::write( std::string const & fileName, EncryptionKey const & key )
 
   os.writeRandomIv();
 
-  FileHeader header;
+  BundleFileHeader header;
   header.set_version( FileFormatVersion );
-  Message::serialize( header, os );
-
   const_sptr<Compression> compression = Compression::default_compression;
-  info.set_compression_method( compression->getName() );
+  header.set_compression_method( compression->getName() );
+  Message::serialize( header, os );
 
   Message::serialize( info, os );
   os.writeAdler32();
@@ -49,8 +48,6 @@ void Creator::write( std::string const & fileName, EncryptionKey const & key )
 
   encoder->setInput( payload.data(), payload.size() );
 
-  // deliberately break the test: ((uint8_t*)strm.next_in)[10] = 7;
-
   for ( ; ; )
   {
     {
@@ -83,7 +80,7 @@ Reader::Reader( string const & fileName, EncryptionKey const & key )
 
   is.consumeRandomIv();
 
-  FileHeader header;
+  BundleFileHeader header;
   Message::parse( header, is );
 
   if ( header.version() != FileFormatVersion )
@@ -99,7 +96,7 @@ Reader::Reader( string const & fileName, EncryptionKey const & key )
 
   payload.resize( payloadSize );
 
-  sptr<EnDecoder> decoder = Compression::findCompression( info.compression_method() )->createDecoder();
+  sptr<EnDecoder> decoder = Compression::findCompression( header.compression_method() )->createDecoder();
 
   decoder->setOutput( &payload[ 0 ], payload.size() );
 

tests/bundle/bundle.pro

@@ -46,4 +46,5 @@ HEADERS += \
     ../../message.hh \
     ../../hex.hh \
     ../../compression.hh \
+    ../../message.hh \
     ../../zbackup.pb.h

tests/bundle/test_bundle.cc

@@ -12,9 +12,68 @@
 #include "../../adler32.hh"
 #include "../../bundle.hh"
 #include "../../compression.hh"
+#include "../../message.hh"
 
 char tmpbuf[100];
 
+void testCompatibility()
+{
+  // The LZO code uses a different file header than the previous code
+  // because it adds the compression_method field. Nevertheless, it
+  // must be compatible with previous code.
+
+  TmpMgr tmpMgr( "/dev/shm" );
+  sptr< TemporaryFile > tempFile = tmpMgr.makeTemporaryFile();
+  std::string fileName = tempFile->getFileName();
+
+  EncryptionKey noKey( std::string(), NULL );
+
+
+  // Write old header, read as new header
+  {
+    {
+      EncryptedFile::OutputStream os( fileName.c_str(), noKey, Encryption::ZeroIv );
+
+      FileHeader header;
+      header.set_version( 42 );
+      Message::serialize( header, os );
+    }
+
+    {
+      EncryptedFile::InputStream is( fileName.c_str(), noKey, Encryption::ZeroIv );
+
+      BundleFileHeader header;
+      Message::parse( header, is );
+
+      CHECK( header.version()            == 42,     "version is wrong when reading old header with new program" );
+      CHECK( header.compression_method() == "lzma", "compression_method is wrong when reading old header with new program" );
+    }
+  }
+
+  // Write new header, read as old header
+  {
+    {
+      EncryptedFile::OutputStream os( fileName.c_str(), noKey, Encryption::ZeroIv );
+
+      BundleFileHeader header;
+      header.set_version( 42 );
+      Message::serialize( header, os );
+    }
+
+    {
+      EncryptedFile::InputStream is( fileName.c_str(), noKey, Encryption::ZeroIv );
+
+      FileHeader header;
+      Message::parse( header, is );
+
+      CHECK( header.version() == 42,     "version is wrong when reading new header with old program" );
+      // cannot check compression_method because the field doesn't exist
+    }
+  }
+
+  printf("compatibility test successful.\n");
+}
+
 void readAndWrite( EncryptionKey const & key,
   const_sptr<Compression> compression1, const_sptr<Compression> compression2 )
 {
@@ -83,6 +142,8 @@ int main()
   EncryptionKey key( "blah", &keyInfo );
   EncryptionKey noKey( std::string(), NULL );
 
+  testCompatibility();
+
   std::vector< const_sptr<Compression> > compressions;
   for ( Compression::iterator it = Compression::begin(); it!=Compression::end(); ++it ) {
     printf( "supported compression: %s\n", (*it)->getName().c_str() );

zbackup.proto

@@ -53,14 +53,6 @@ message BundleInfo
 
   // A sequence of chunk records
   repeated ChunkRecord chunk_record = 1;
-
-  // Compression method that is used for this file
-  // If the program doesn't support that field, it will try LZMA. If it is
-  // LZMA, that will work. If it isn't, liblzma will recognize this and abort.
-  //NOTE If I was mainting this code (instead of adding this without asking for
-  //     permission or support), I would probably use a string and I would
-  //     definetly use tag 2 instead of 101.
-  optional string compression_method = 101 [default = "lzma"];
 }
 
 message FileHeader
@@ -69,6 +61,17 @@ message FileHeader
   required uint32 version = 1;
 }
 
+message BundleFileHeader
+{
+  // File format version
+  required uint32 version = 1;
+
+  // Compression method that is used for this file
+  // If the program doesn't support that field, it will try LZMA. If it is
+  // LZMA, that will work. If it isn't, liblzma will recognize this and abort.
+  optional string compression_method = 2 [default = "lzma"];
+}
+
 message IndexBundleHeader
 {
   // Id of the bundle following in the stream. If not present, indicates the