Improved GC and Shadow File Handling

- Every command now returns an output string, or at least has an
  opportunity to do so.
- TDB::gc is only performed a) when allowed, and b) when the command
  will display line numbers.
- updateShadowFile is only performed when a) shadow updates are allowed,
  and either b) when a command is guaranteed to have modified a task or
  c) when TDB:gc has already made changes.

src/command.cpp

@@ -48,8 +48,10 @@
 #endif
 
 ////////////////////////////////////////////////////////////////////////////////
-void handleAdd (TDB& tdb, T& task, Config& conf)
+std::string handleAdd (TDB& tdb, T& task, Config& conf)
 {
+  std::stringstream out;
+
   char entryTime[16];
   sprintf (entryTime, "%u", (unsigned int) time (NULL));
   task.setAttribute ("entry", entryTime);
@@ -86,6 +88,8 @@ void handleAdd (TDB& tdb, T& task, Config& conf)
 
   if (!tdb.addT (task))
     throw std::string ("Could not create new task.");
+
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -547,8 +551,10 @@ std::string handleStop (TDB& tdb, T& task, Config& conf)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void handleDone (TDB& tdb, T& task, Config& conf)
+std::string handleDone (TDB& tdb, T& task, Config& conf)
 {
+  std::stringstream out;
+
   if (!tdb.completeT (task))
     throw std::string ("Could not mark task as completed.");
 
@@ -566,11 +572,14 @@ void handleDone (TDB& tdb, T& task, Config& conf)
   }
 
   nag (tdb, task, conf);
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void handleExport (TDB& tdb, T& task, Config& conf)
+std::string handleExport (TDB& tdb, T& task, Config& conf)
 {
+  std::stringstream out;
+
   // Use the description as a file name, then clobber the description so the
   // file name isn't used for filtering.
   std::string file = trim (task.getDescription ());
@@ -610,11 +619,14 @@ void handleExport (TDB& tdb, T& task, Config& conf)
   }
   else
     throw std::string ("You must specify a file to write to.");
+
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void handleModify (TDB& tdb, T& task, Config& conf)
+std::string handleModify (TDB& tdb, T& task, Config& conf)
 {
+  std::stringstream out;
   std::vector <T> all;
   tdb.pendingT (all);
 
@@ -695,11 +707,12 @@ void handleModify (TDB& tdb, T& task, Config& conf)
         tdb.modifyT (original);
       }
 
-      return;
+      return out.str ();
     }
   }
 
   throw std::string ("Task not found.");
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////

src/task.cpp

@@ -27,6 +27,7 @@
 #include <iostream>
 #include <iomanip>
 #include <fstream>
+#include <sstream>
 #include <sys/types.h>
 #include <stdio.h>
 #include <string.h>
@@ -47,8 +48,9 @@
 #endif
 
 ////////////////////////////////////////////////////////////////////////////////
-static void shortUsage (Config& conf)
+static std::string shortUsage (Config& conf)
 {
+  std::stringstream out;
   Table table;
   int width = conf.get ("defaultwidth", 80);
 #ifdef HAVE_LIBNCURSES
@@ -192,21 +194,22 @@ static void shortUsage (Config& conf)
     table.addCell (row, 2, description);
   }
 
-  std::cout << table.render ()
+  out << table.render ()
       << std::endl
       << "See http://www.beckingham.net/task.html for the latest releases and a "
       << "full tutorial.  New releases containing fixes and enhancements are "
       << "made frequently."
       << std::endl
       << std::endl;
+
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-static void longUsage (Config& conf)
+static std::string longUsage (Config& conf)
 {
-  shortUsage (conf);
+  std::stringstream out;
-
+  out << shortUsage (conf)
-  std::cout
       << "ID is the numeric identifier displayed by the 'task list' command." << "\n"
       <<                                                                         "\n"
       << "Tags are arbitrary words, any quantity:"                            << "\n"
@@ -234,6 +237,8 @@ static void longUsage (Config& conf)
       << "Many characters have special meaning to the shell, including:"      << "\n"
       << "  $ ! ' \" ( ) ; \\ ` * ? { } [ ] < > | & % # ~"                    << "\n"
       << std::endl;
+
+  return out.str ();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -790,34 +795,49 @@ std::string runTaskCommand (
   T task;
   parse (args, command, task, conf);
 
-  std::string out = "";
+  bool gcMod  = false; // Change occurred by way of gc.
+  bool cmdMod = false; // Change occurred by way of command type.
+  std::string out;
 
-       if (command == "" && task.getId ())  {                          handleModify         (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
+  // Read-only commands with no side effects.
-  else if (command == "add")                {                          handleAdd            (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
+       if (command == "export")             { out = handleExport         (tdb, task, conf); }
-  else if (command == "done")               {                          handleDone           (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "export")             {                          handleExport         (tdb, task, conf         );                                           }
   else if (command == "projects")           { out = handleProjects       (tdb, task, conf); }
   else if (command == "tags")               { out = handleTags           (tdb, task, conf); }
   else if (command == "info")               { out = handleInfo           (tdb, task, conf); }
-  else if (command == "undelete")           {                    out = handleUndelete       (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "delete")             {                    out = handleDelete         (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "start")              {                    out = handleStart          (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "stop")               {                    out = handleStop           (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "undo")               {                    out = handleUndo           (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
   else if (command == "stats")              { out = handleReportStats    (tdb, task, conf); }
-  else if (command == "completed")          { if (gc) tdb.gc (); out = handleCompleted      (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); } // TODO replace with Custom
+  else if (command == "history")            { out = handleReportHistory  (tdb, task, conf); }
-  else if (command == "summary")            { if (gc) tdb.gc (); out = handleReportSummary  (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
+  else if (command == "ghistory")           { out = handleReportGHistory (tdb, task, conf); }
-  else if (command == "next")               { if (gc) tdb.gc (); out = handleReportNext     (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); } // TODO replace with Custom
+  else if (command == "calendar")           { out = handleReportCalendar (tdb, task, conf); }
-  else if (command == "history")            { if (gc) tdb.gc (); out = handleReportHistory  (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
+  else if (command == "summary")            { out = handleReportSummary  (tdb, task, conf); }
-  else if (command == "ghistory")           { if (gc) tdb.gc (); out = handleReportGHistory (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "calendar")           { if (gc) tdb.gc (); out = handleReportCalendar (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); }
-  else if (command == "active")             { if (gc) tdb.gc (); out = handleReportActive   (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); } // TODO replace with Custom
-  else if (command == "overdue")            { if (gc) tdb.gc (); out = handleReportOverdue  (tdb, task, conf         ); if (shadow) updateShadowFile (tdb, conf); } // TODO replace with Custom
   else if (command == "colors")             { out = handleColor          (           conf); }
   else if (command == "version")            { out = handleVersion        (           conf); }
-  else if (command == "help")               {                          longUsage            (           conf         );                                           }
+  else if (command == "help")               { out = longUsage            (           conf); }
-  else if (isCustomReport (command))        { if (gc) tdb.gc (); out = handleCustomReport   (tdb, task, conf, command); if (shadow) updateShadowFile (tdb, conf); } // New Custom reports
+
-  else                                      {                          shortUsage           (           conf         );                                           }
+  // Commands that cause updates.
+  else if (command == "" && task.getId ())  { cmdMod = true; out = handleModify   (tdb, task, conf); }
+  else if (command == "add")                { cmdMod = true; out = handleAdd      (tdb, task, conf); }
+  else if (command == "done")               { cmdMod = true; out = handleDone     (tdb, task, conf); }
+  else if (command == "undelete")           { cmdMod = true; out = handleUndelete (tdb, task, conf); }
+  else if (command == "delete")             { cmdMod = true; out = handleDelete   (tdb, task, conf); }
+  else if (command == "start")              { cmdMod = true; out = handleStart    (tdb, task, conf); }
+  else if (command == "stop")               { cmdMod = true; out = handleStop     (tdb, task, conf); }
+  else if (command == "undo")               { cmdMod = true; out = handleUndo     (tdb, task, conf); }
+
+  // Command that display IDs and therefore need TDB::gc first.
+
+  else if (command == "completed")          { if (gc) gcMod = tdb.gc (); out = handleCompleted     (tdb, task, conf); }
+  else if (command == "next")               { if (gc) gcMod = tdb.gc (); out = handleReportNext    (tdb, task, conf); }
+  else if (command == "active")             { if (gc) gcMod = tdb.gc (); out = handleReportActive  (tdb, task, conf); }
+  else if (command == "overdue")            { if (gc) gcMod = tdb.gc (); out = handleReportOverdue (tdb, task, conf); }
+  else if (isCustomReport (command))        { if (gc) gcMod = tdb.gc (); out = handleCustomReport  (tdb, task, conf, command); }
+
+  // If the command is not recognized, display usage.
+  else                                      { out = shortUsage (conf); }
+
+  // Only update the shadow file if such an update was not suppressed (shadow),
+  // and if an actual change occurred (gcMod || cmdMod).
+  if (shadow && (gcMod || cmdMod))
+    updateShadowFile (tdb, conf);
 
   return out;
 }

src/task.h

@@ -74,10 +74,10 @@ std::string runTaskCommand (int, char**, TDB&, Config&, bool gc = true, bool sha
 std::string runTaskCommand (std::vector <std::string>&, TDB&, Config&, bool gc = false, bool shadow = false);
 
 // command.cpp
-void handleAdd (TDB&, T&, Config&);
+std::string handleAdd (TDB&, T&, Config&);
-void handleExport (TDB&, T&, Config&);
+std::string handleExport (TDB&, T&, Config&);
-void handleDone (TDB&, T&, Config&);
+std::string handleDone (TDB&, T&, Config&);
-void handleModify (TDB&, T&, Config&);
+std::string handleModify (TDB&, T&, Config&);
 std::string handleProjects (TDB&, T&, Config&);
 std::string handleTags (TDB&, T&, Config&);
 std::string handleUndelete (TDB&, T&, Config&);