cmFileCommand: Do not log raw protocol data from curl (#15589)

Teach cmFileCommandCurlDebugCallback to filter the debug data by type
and show only summary information instead of the raw data.  This avoids
allocating memory for all data transferred by UPLOAD or DOWNLOAD.

Source/cmFileCommand.cxx

@@ -2798,13 +2798,36 @@ namespace {
 
 
   static size_t
-  cmFileCommandCurlDebugCallback(CURL *, curl_infotype, char *chPtr,
+  cmFileCommandCurlDebugCallback(CURL *, curl_infotype type, char *chPtr,
                                  size_t size, void *data)
     {
     cmFileCommandVectorOfChar *vec
       = static_cast<cmFileCommandVectorOfChar*>(data);
-    vec->insert(vec->end(), chPtr, chPtr + size);
-    return size;
+    switch(type)
+      {
+      case CURLINFO_TEXT:
+      case CURLINFO_HEADER_IN:
+      case CURLINFO_HEADER_OUT:
+        vec->insert(vec->end(), chPtr, chPtr + size);
+        break;
+      case CURLINFO_DATA_IN:
+      case CURLINFO_DATA_OUT:
+      case CURLINFO_SSL_DATA_IN:
+      case CURLINFO_SSL_DATA_OUT:
+        {
+        char buf[128];
+        int n = sprintf(buf, "[%" cmIML_INT_PRIu64 " bytes data]\n",
+                        static_cast<cmIML_INT_uint64_t>(size));
+        if (n > 0)
+          {
+          vec->insert(vec->end(), buf, buf + n);
+          }
+        }
+        break;
+      default:
+        break;
+      }
+    return 0;
     }