Teach file(DOWNLOAD|UPLOAD) to timeout after inactivity

Add option INACTIVITY_TIMEOUT to terminate the operation if there is no
progress for more than a given amount of time.

Source/cmFileCommand.cxx

@@ -2614,6 +2614,7 @@ cmFileCommand::HandleDownloadCommand(std::vector<std::string> const& args)
   ++i;
 
   long timeout = 0;
+  long inactivity_timeout = 0;
   std::string verboseLog;
   std::string statusVar;
   std::string expectedMD5sum;
@@ -2634,6 +2635,19 @@ cmFileCommand::HandleDownloadCommand(std::vector<std::string> const& args)
         return false;
         }
       }
+    else if(*i == "INACTIVITY_TIMEOUT")
+      {
+      ++i;
+      if(i != args.end())
+        {
+        inactivity_timeout = atol(i->c_str());
+        }
+      else
+        {
+        this->SetError("DOWNLOAD missing time for INACTIVITY_TIMEOUT.");
+        return false;
+        }
+      }
     else if(*i == "LOG")
       {
       ++i;
@@ -2770,6 +2784,13 @@ cmFileCommand::HandleDownloadCommand(std::vector<std::string> const& args)
     check_curl_result(res, "DOWNLOAD cannot set timeout: ");
     }
 
+  if(inactivity_timeout > 0)
+    {
+    // Give up if there is no progress for a long time.
+    ::curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 1);
+    ::curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, inactivity_timeout);
+    }
+
   // Need the progress helper's scope to last through the duration of
   // the curl_easy_perform call... so this object is declared at function
   // scope intentionally, rather than inside the "if(showProgress)"
@@ -2883,6 +2904,7 @@ cmFileCommand::HandleUploadCommand(std::vector<std::string> const& args)
   ++i;
 
   long timeout = 0;
+  long inactivity_timeout = 0;
   std::string logVar;
   std::string statusVar;
   bool showProgress = false;
@@ -2902,6 +2924,19 @@ cmFileCommand::HandleUploadCommand(std::vector<std::string> const& args)
         return false;
         }
       }
+    else if(*i == "INACTIVITY_TIMEOUT")
+      {
+      ++i;
+      if(i != args.end())
+        {
+        inactivity_timeout = atol(i->c_str());
+        }
+      else
+        {
+        this->SetError("UPLOAD missing time for INACTIVITY_TIMEOUT.");
+        return false;
+        }
+      }
     else if(*i == "LOG")
       {
       ++i;
@@ -3003,6 +3038,13 @@ cmFileCommand::HandleUploadCommand(std::vector<std::string> const& args)
     check_curl_result(res, "UPLOAD cannot set timeout: ");
     }
 
+  if(inactivity_timeout > 0)
+    {
+    // Give up if there is no progress for a long time.
+    ::curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 1);
+    ::curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, inactivity_timeout);
+    }
+
   // Need the progress helper's scope to last through the duration of
   // the curl_easy_perform call... so this object is declared at function
   // scope intentionally, rather than inside the "if(showProgress)"

Source/cmFileCommand.h

@@ -80,10 +80,11 @@ public:
       "  file(RELATIVE_PATH variable directory file)\n"
       "  file(TO_CMAKE_PATH path result)\n"
       "  file(TO_NATIVE_PATH path result)\n"
-      "  file(DOWNLOAD url file [TIMEOUT timeout] [STATUS status] [LOG log]\n"
-      "       [EXPECTED_MD5 sum] [SHOW_PROGRESS])\n"
-      "  file(UPLOAD filename url [TIMEOUT timeout] [STATUS status]\n"
-      "       [LOG log] [SHOW_PROGRESS])\n"
+      "  file(DOWNLOAD url file [INACTIVITY_TIMEOUT timeout]\n"
+      "       [TIMEOUT timeout] [STATUS status] [LOG log] [SHOW_PROGRESS]\n"
+      "       [EXPECTED_MD5 sum])\n"
+      "  file(UPLOAD filename url [INACTIVITY_TIMEOUT timeout]\n"
+      "       [TIMEOUT timeout] [STATUS status] [LOG log] [SHOW_PROGRESS])\n"
       "WRITE will write a message into a file called 'filename'. It "
       "overwrites the file if it already exists, and creates the file "
       "if it does not exist.\n"
@@ -161,6 +162,8 @@ public:
       "numeric error means no error in the operation. "
       "If TIMEOUT time is specified, the operation will "
       "timeout after time seconds, time should be specified as an integer. "
+      "The INACTIVITY_TIMEOUT specifies an integer number of seconds of "
+      "inactivity after which the operation should terminate. "
       "If EXPECTED_MD5 sum is specified, the operation will verify that the "
       "downloaded file's actual md5 sum matches the expected value. If it "
       "does not match, the operation fails with an error. "
@@ -176,6 +179,8 @@ public:
       "numeric error means no error in the operation. "
       "If TIMEOUT time is specified, the operation will "
       "timeout after time seconds, time should be specified as an integer. "
+      "The INACTIVITY_TIMEOUT specifies an integer number of seconds of "
+      "inactivity after which the operation should terminate. "
       "If SHOW_PROGRESS is specified, progress information will be printed "
       "as status messages until the operation is complete."
       "\n"