From c29682b91f1012cd1586cb655a2ebb46576fa5f8 Mon Sep 17 00:00:00 2001
From: Paul Beckingham <paul@beckingham.net>
Date: Sun, 28 Jun 2009 12:23:46 -0400
Subject: [PATCH] Enhancement - undo

- Now creates/opens/closes undo.data file.
- All new tasks are logged in undo.data file.
---
 src/Location.cpp |  3 +++
 src/Location.h   |  1 +
 src/TDB.cpp      | 42 ++++++++++++++++++++++++++++++++++++------
 src/TDB.h        |  1 +
 4 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/src/Location.cpp b/src/Location.cpp
index 984a2da98..667eaebc4 100644
--- a/src/Location.cpp
+++ b/src/Location.cpp
@@ -32,6 +32,7 @@ Location::Location ()
 : path ("")
 , pending (NULL)
 , completed (NULL)
+, undo (NULL)
 {
 }
 
@@ -47,6 +48,7 @@ Location::Location (const Location& other)
   path      = other.path;
   pending   = other.pending;
   completed = other.completed;
+  undo      = other.undo;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -57,6 +59,7 @@ Location& Location::operator= (const Location& other)
     path      = other.path;
     pending   = other.pending;
     completed = other.completed;
+    undo      = other.undo;
   }
 
   return *this;
diff --git a/src/Location.h b/src/Location.h
index 4a93ea7df..65cb66ee7 100644
--- a/src/Location.h
+++ b/src/Location.h
@@ -43,6 +43,7 @@ public:
   std::string path;
   FILE*       pending;
   FILE*       completed;
+  FILE*       undo;
 };
 
 #endif
diff --git a/src/TDB.cpp b/src/TDB.cpp
index f5efb43f0..81f1f21d5 100644
--- a/src/TDB.cpp
+++ b/src/TDB.cpp
@@ -124,6 +124,7 @@ void TDB::lock (bool lockFile /* = true */)
   {
     location->pending   = openAndLock (location->path + "/pending.data");
     location->completed = openAndLock (location->path + "/completed.data");
+    location->undo      = openAndLock (location->path + "/undo.data");
   }
 
   mAllOpenAndLocked = true;
@@ -147,6 +148,10 @@ void TDB::unlock ()
       fflush (location->completed);
       fclose (location->completed);
       location->completed = NULL;
+
+      fflush (location->undo);
+      fclose (location->undo);
+      location->completed = NULL;
     }
 
     mAllOpenAndLocked = false;
@@ -275,9 +280,6 @@ int TDB::loadCompleted (std::vector <Task>& tasks, Filter& filter)
     char line[T_LINE_MAX];
     foreach (location, mLocations)
     {
-      // TODO If the filter contains Status:x where x is not deleted or
-      //      completed, then this can be skipped.
-
       line_number = 1;
       file = location->path + "/completed.data";
 
@@ -315,7 +317,6 @@ int TDB::loadCompleted (std::vector <Task>& tasks, Filter& filter)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// TODO Write to transaction log.
 // Note: mLocations[0] is where all tasks are written.
 void TDB::add (const Task& task)
 {
@@ -324,14 +325,12 @@ void TDB::add (const Task& task)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// TODO Write to transaction log.
 void TDB::update (const Task& task)
 {
   mModified.push_back (task);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// TODO Writes all, including comments
 // Interestingly, only the pending file gets written to.  The completed file is
 // only modified by TDB::gc.
 int TDB::commit ()
@@ -351,6 +350,10 @@ int TDB::commit ()
       fputs (task->composeF4 ().c_str (), mLocations[0].pending);
     }
 
+    fseek (mLocations[0].undo, 0, SEEK_END);
+    foreach (task, mNew)
+      writeUndo (*task, mLocations[0].undo);
+
     mNew.clear ();
     return quantity;
   }
@@ -377,6 +380,13 @@ int TDB::commit ()
       foreach (task, mPending)
         fputs (task->composeF4 ().c_str (), mLocations[0].pending);
     }
+
+/*
+    // Update the undo log.
+    fseek (mLocations[0].undo, 0, SEEK_END);
+    foreach (task, mPending)
+      writeUndo (*task, mLocations[0].undo);
+*/
   }
 
   return quantity;
@@ -498,3 +508,23 @@ FILE* TDB::openAndLock (const std::string& file)
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+void TDB::writeUndo (const Task& after, FILE* file)
+{
+  Timer t ("TDB::writeUndo");
+
+  // TODO Locate "before" task (match on uuid).
+
+  fprintf (file,
+           "time %u\nnew %s\n---\n",
+           (unsigned int) time (NULL),
+           after.composeF4 ().c_str ());
+/*
+  fprintf (file,
+           "time %u\nold %s\nnew %s\n---\n",
+           (unsigned int) time (NULL),
+           before.composeF4 ().c_str (),
+           after.composeF4 ().c_str ());
+*/
+}
+
+////////////////////////////////////////////////////////////////////////////////
diff --git a/src/TDB.h b/src/TDB.h
index 5112e4ad9..f4a42bf5b 100644
--- a/src/TDB.h
+++ b/src/TDB.h
@@ -64,6 +64,7 @@ public:
 
 private:
   FILE* openAndLock (const std::string&);
+  void writeUndo (const Task&, FILE*);
 
 private:
   std::vector <Location> mLocations;