Added --force-save option.

--force-save option saves download with --save-session option even if
the download is completed or removed. This may be useful to save
BitTorrent seeding which is recognized as completed state.  The
default value is false.

src/OptionHandlerFactory.cc

@@ -370,6 +370,19 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->setChangeOptionForReserved(true);
     handlers.push_back(op);
   }
+  {
+    OptionHandler* op(new BooleanOptionHandler
+                      (PREF_FORCE_SAVE,
+                       TEXT_FORCE_SAVE,
+                       A2_V_FALSE,
+                       OptionHandler::OPT_ARG));
+    op->addTag(TAG_ADVANCED);
+    op->setInitialOption(true);
+    op->setChangeOption(true);
+    op->setChangeGlobalOption(true);
+    op->setChangeOptionForReserved(true);
+    handlers.push_back(op);
+  }
   {
     OptionHandler* op(new BooleanOptionHandler
                       (PREF_FORCE_SEQUENTIAL,

src/SessionSerializer.cc

@@ -159,7 +159,13 @@ bool SessionSerializer::save(BufferedFile& fp) const
         results.begin(), eoi = results.end(); itr != eoi; ++itr) {
     if((*itr)->result == error_code::FINISHED ||
        (*itr)->result == error_code::REMOVED) {
-      continue;
+      if((*itr)->option->getAsBool(PREF_FORCE_SAVE)) {
+        if(!writeDownloadResult(fp, metainfoCache, *itr)) {
+          return false;
+        }
+      } else {
+        continue;
+      }
     } else if((*itr)->result == error_code::IN_PROGRESS) {
       if(saveInProgress_) {
         if(!writeDownloadResult(fp, metainfoCache, *itr)) {

src/prefs.cc

@@ -336,6 +336,8 @@ const Pref* PREF_CHECKSUM = makePref("checksum");
 const Pref* PREF_STOP_WITH_PROCESS = makePref("stop-with-process");
 // value: true | false
 const Pref* PREF_ENABLE_MMAP = makePref("enable-mmap");
+// value: true | false
+const Pref* PREF_FORCE_SAVE = makePref("force-save");
 
 /**
  * FTP related preferences

src/prefs.h

@@ -279,6 +279,8 @@ extern const Pref* PREF_CHECKSUM;
 extern const Pref* PREF_STOP_WITH_PROCESS;
 // value: true | false
 extern const Pref* PREF_ENABLE_MMAP;
+// value: true | false
+extern const Pref* PREF_FORCE_SAVE;
 
 /**
  * FTP related preferences

src/usage_text.h

@@ -909,3 +909,8 @@
     "                              downloads added by aria2.addTorrent or\n" \
     "                              aria2.addMetalink will not be saved by\n" \
     "                              --save-session option.")
+#define TEXT_FORCE_SAVE                         \
+  _(" --force-save[=true|false]    Save download with --save-session option even\n" \
+    "                              if the download is completed or removed. This\n" \
+    "                              may be useful to save BitTorrent seeding which\n" \
+    "                              is recognized as completed state.")