Bug Workaround - locking

- Added support for the "locking" configuration variable that disables
  file locking.  This can be helpful to folks who use task on Solaris,
  and store their task data files on an NFS mount.

src/Config.cpp

@@ -132,6 +132,7 @@ void Config::createDefault (const std::string& home)
         fprintf (out, "color=on\n");
         fprintf (out, "due=7\n");
         fprintf (out, "nag=You have higher priority tasks.\n");
+        fprintf (out, "locking=on\n");
 
         fprintf (out, "color.overdue=bold_red\n");
         fprintf (out, "color.due=bold_yellow\n");
@@ -222,11 +223,13 @@ bool Config::get (const std::string& key, bool default_value)
   {
     std::string value = lowerCase ((*this)[key]);
 
-    if (value == "t"    ||
-        value == "true" ||
-        value == "1"    ||
-        value == "yes"  ||
-        value == "on")
+    if (value == "t"      ||
+        value == "true"   ||
+        value == "1"      ||
+        value == "yes"    ||
+        value == "on"     ||
+        value == "enable" ||
+        value == "enabled")
       return true;
 
     return false;

src/TDB.cpp

@@ -38,6 +38,7 @@ TDB::TDB ()
 : mPendingFile ("")
 , mCompletedFile ("")
 , mId (1)
+, mNoLock (false)
 {
 }
 
@@ -289,6 +290,9 @@ bool TDB::modifyT (const T& t)
 ////////////////////////////////////////////////////////////////////////////////
 bool TDB::lock (FILE* file) const
 {
+  if (mNoLock)
+    return true;
+
   return flock (fileno (file), LOCK_EX) ? false : true;
 }
 
@@ -300,8 +304,9 @@ bool TDB::overwritePending (std::vector <T>& all)
   if ((out = fopen (mPendingFile.c_str (), "w")))
   {
     int retry = 0;
-    while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
-      delay (0.25);
+    if (!mNoLock)
+      while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
+        delay (0.1);
 
     std::vector <T>::iterator it;
     for (it = all.begin (); it != all.end (); ++it)
@@ -322,8 +327,9 @@ bool TDB::writePending (const T& t)
   if ((out = fopen (mPendingFile.c_str (), "a")))
   {
     int retry = 0;
-    while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
-      delay (0.25);
+    if (!mNoLock)
+      while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
+        delay (0.1);
 
     fputs (t.compose ().c_str (), out);
 
@@ -342,8 +348,9 @@ bool TDB::writeCompleted (const T& t)
   if ((out = fopen (mCompletedFile.c_str (), "a")))
   {
     int retry = 0;
-    while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
-      delay (0.25);
+    if (!mNoLock)
+      while (flock (fileno (out), LOCK_EX) && ++retry <= 3)
+        delay (0.1);
 
     fputs (t.compose ().c_str (), out);
 
@@ -367,8 +374,9 @@ bool TDB::readLockedFile (
     if ((in = fopen (file.c_str (), "r")))
     {
       int retry = 0;
-      while (flock (fileno (in), LOCK_EX) && ++retry <= 3)
-        delay (0.25);
+      if (!mNoLock)
+        while (flock (fileno (in), LOCK_EX) && ++retry <= 3)
+          delay (0.1);
 
       char line[T_LINE_MAX];
       while (fgets (line, T_LINE_MAX, in))
@@ -432,4 +440,10 @@ int TDB::nextId ()
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+void TDB::noLock ()
+{
+  mNoLock = true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
 

src/TDB.h

@@ -51,6 +51,8 @@ public:
   int gc                ();
   int nextId            ();
 
+  void noLock           ();
+
 private:
   bool lock             (FILE*) const;
   bool overwritePending (std::vector <T>&);
@@ -62,6 +64,7 @@ private:
   std::string mPendingFile;
   std::string mCompletedFile;
   int mId;
+  bool mNoLock;
 };
 
 #endif

src/command.cpp

@@ -367,8 +367,8 @@ std::string handleVersion (Config& conf)
     "blanklines color color.active color.due color.overdue color.pri.H "
     "color.pri.L color.pri.M color.pri.none color.recurring color.tagged "
     "confirmation curses data.location dateformat default.command "
-    "default.priority defaultwidth due monthsperline nag newest next oldest "
-    "project shadow.command shadow.file shadow.notify";
+    "default.priority defaultwidth due locking monthsperline nag newest next "
+    "oldest project shadow.command shadow.file shadow.notify";
 
   // This configuration variable is supported, but not documented.  It exists
   // so that unit tests can force color to be on even when the output from task

src/task.cpp

@@ -299,6 +299,10 @@ int main (int argc, char** argv)
     std::string dataLocation = expandPath (conf.get ("data.location"));
     tdb.dataDirectory (dataLocation);
 
+    // Allow user override of file locking.  Solaris/NFS machines may want this.
+    if (! conf.get ("locking", true))
+      tdb.noLock ();
+
     // Check for silly shadow file settings.
     std::string shadowFile = expandPath (conf.get ("shadow.file"));
     if (shadowFile != "")