cta/CTA#139 cta af ls --vid XXXXX command times out if there are many files on a tape

The "cta af ls" command now sends several rows back to the client
in a single reply.

cmdline/CTACmdMain.cpp

@@ -157,27 +157,21 @@ int sendCommand(const int argc, const char **argv) {
   {
     uint64_t readOffset = 1; // The first character at offset 0 has already been read
     uint32_t bytesRead = 0;
+    const size_t bufSize = 20480;
+    std::unique_ptr<char []> buf(new char[bufSize]);
     do {
       bytesRead = 0;
-      char buf[1024];
-      memset(buf, 0, sizeof(buf));
-      const XrdCl::XRootDStatus readStatus = xrootFile.Read(readOffset, sizeof(buf) - 1, buf, bytesRead);
+      memset(buf.get(), 0, bufSize);
+      const XrdCl::XRootDStatus readStatus = xrootFile.Read(readOffset, bufSize - 1, buf.get(), bytesRead);
       if(!readStatus.IsOK()) {
         throw std::runtime_error(std::string("Failed to read ") + cmdPath + ": " + readStatus.ToStr());
       }
 
       if(bytesRead > 0) {
-        for(std::string::size_type i = 0; i < bytesRead; i++) {
-          const char c = buf[i];
-          if(0 == c) {
-            std::cout << "<NULL>";
-          } else {
-            std::cout << c;
-          }
-        }
+        std::cout << buf.get();
 
         if(writeToStderr) {
-          std::cerr<<buf;
+          std::cerr << buf.get();
         }
       }
 

xroot_plugins/ListArchiveFilesCmd.cpp

@@ -111,10 +111,15 @@ XrdSfsXferSize ListArchiveFilesCmd::read(XrdSfsFileOffset offset, char *buffer,
 // refreshReadBuffer
 //------------------------------------------------------------------------------
 void ListArchiveFilesCmd::refreshReadBuffer() {
+  // Note that one archive file may have more than one tape file
+  const uint32_t nbArchiveFilesToFetch = 100;
+  uint32_t nbFetchedArchiveFiles = 0;
+
   m_readBuffer.clear();
 
-  if(m_archiveFileItor->hasMore()) {
+  while(m_archiveFileItor->hasMore() && nbArchiveFilesToFetch > nbFetchedArchiveFiles) {
     const common::dataStructures::ArchiveFile archiveFile = m_archiveFileItor->next();
+    nbFetchedArchiveFiles++;
     for(auto copyNbToTapeFile: archiveFile.tapeFiles) {
       const auto copyNb = copyNbToTapeFile.first;
       const common::dataStructures::TapeFile &tapeFile = copyNbToTapeFile.second;