cta/CTA#584 Verifies checksum before writing disk replica

Writing the disk replica will fail if the checksum of the file read
from tape does not match the checksum in the CTA catalogue.

tapeserver/castor/tape/tapeserver/daemon/TapeReadTask.hpp

@@ -127,11 +127,7 @@ public:
           // end of file. append() also protects against reading too big tape blocks.
           while (mb->m_payload.append(*rf)) {
             tapeBlock++;
-            if(isVerifyOnly) {
-              // Normally, the checksum is calculated in DiskWriteTask::execute(). In verification-only mode, there is no
-              // write to disk. As we need to validate the checksum, we calculate it here.
-              checksum_adler32 = mb->m_payload.adler32(checksum_adler32);
-            }
+            checksum_adler32 = mb->m_payload.adler32(checksum_adler32);
           }
         } catch (const cta::exception::EndOfFile&) {
           // append() signaled the end of the file.
@@ -151,17 +147,18 @@ public:
           // Don't write the file to disk
           mb->markAsVerifyOnly();
         }
+        // If we reached the end of the file, validate the checksum (throws an exception on bad checksum)
+        if(!stillReading) {
+          tapeReadChecksum.insert(cta::checksum::ADLER32, checksum_adler32);
+          m_retrieveJob->archiveFile.checksumBlob.validate(tapeReadChecksum);
+        }
         // Pass the block to the disk write task
         m_fifo.pushDataBlock(mb);
         mb=NULL;
         watchdog.notify(blockSize);
         localStats.waitReportingTime += timer.secs(cta::utils::Timer::resetCounter);
       } //end of while(stillReading)
-      if(isVerifyOnly) {
-        tapeReadChecksum.insert(cta::checksum::ADLER32, checksum_adler32);
-        m_retrieveJob->archiveFile.checksumBlob.validate(tapeReadChecksum);
-      }
-      //  we have to signal the end of the tape read to the disk write task.
+      // We have to signal the end of the tape read to the disk write task.
       m_fifo.pushDataBlock(NULL);
       // Log the successful transfer
       localStats.totalTime = localTime.secs();
@@ -195,19 +192,18 @@ public:
 	    .add("userFilesCount",localStats.userFilesCount)
 	    .add("userBytesCount",localStats.userBytesCount)
 	    .add("verifiedFilesCount",localStats.verifiedFilesCount)
-	    .add("verifiedBytesCount",localStats.verifiedBytesCount);
-      if(isVerifyOnly) {
-        params.add("checksumType", "ADLER32")
-              .add("checksumValue", cta::checksum::ChecksumBlob::ByteArrayToHex(tapeReadChecksum.at(cta::checksum::ADLER32)));
-      }
+	    .add("verifiedBytesCount",localStats.verifiedBytesCount)
+            .add("checksumType", "ADLER32")
+            .add("checksumValue", cta::checksum::ChecksumBlob::ByteArrayToHex(tapeReadChecksum.at(cta::checksum::ADLER32)));
       lc.log(cta::log::INFO, "File successfully read from tape");
       // Add the local counts to the session's
       stats.add(localStats);
     } //end of try
     catch (const cta::exception::Exception & ex) {
-      //we end up there because :
-      //-- openReadFile brought us here (cant position to the file)
+      // We end up here because:
+      //-- openReadFile brought us here (can't position to the file)
       //-- m_payload.append brought us here (error while reading the file)
+      //-- Checksum validation failed (after reading the last block from tape)
       // Record the error in the watchdog
       if (currentErrorToCount.size()) {
         watchdog.addToErrorCount(currentErrorToCount);