# 
# patch "ChangeLog"
#  from [6d6babd353a051b7b5d6028319c3c98c8d81f7b2]
#    to [8828e452a0ac7dcf37a61eef52a908415cb90615]
# 
# patch "automate.cc"
#  from [5416a4b51b9029e98cede29f658fb1120ee7bb65]
#    to [b303e2282502365cfd91af081afa85b6df03de8b]
# 
# patch "commands.cc"
#  from [002c7e8b171019ed9c19cb1f15dcfebdec5c1257]
#    to [e91738f6920ce61beca85f8703a8efbab058a53e]
# 
# patch "database.cc"
#  from [7fbf000b889c6a9e67179e405279c17c08f8b1ff]
#    to [d2b9a3f2fb7aae0006bd60e1266f0d9e7f882bfd]
# 
# patch "database.hh"
#  from [5e52b0b84dd9cdcd155ee9af48481f8476ac2d8b]
#    to [a25c05b9b4ae523a61d846f7d21817cde40580bb]
# 
========================================================================
--- ChangeLog	6d6babd353a051b7b5d6028319c3c98c8d81f7b2
+++ ChangeLog	8828e452a0ac7dcf37a61eef52a908415cb90615
@@ -1,3 +1,15 @@
+2005-11-27  Grahame Bowland  <address@hidden>
+
+	* automate.cc (automate_certs,automate_keys): use non-exclusive 
+	transaction guard
+	* commands.cc (ls_certs,ls_keys,cat): use non-exclusive 
+	transaction guard
+	* database.cc (begin_transaction): used BEGIN DEFERRED (only attempt 
+	exclusive lock once a write is attempted on DB) when not exclusive
+	(transaction_guard::transaction_guard): new argument exclusive indicating 
+	whether an immediate exclusive lock is requested, defaults to true
+	* database.hh: update prototype for transaction_guard
+
 2005-11-26  Nathaniel Smith  <address@hidden>
 
 	* UPGRADE: Add note about serve changing syntax.
@@ -33,7 +45,7 @@
 	* configure.ac, Makefile.am, po/Makevars: Avoid using xgettext's
 	--flag option on versions that do not support it.
 
-2005-11-26  Grahame Bowland  <address@hidden>
+2005-11-26  Grahame Bowland  <address@hidden>
 
 	* automate.cc (automate_stdio) add wrapper function to read()
 	so that loops will not wind backwards possibly overrunning buffers
========================================================================
--- automate.cc	5416a4b51b9029e98cede29f658fb1120ee7bb65
+++ automate.cc	b303e2282502365cfd91af081afa85b6df03de8b
@@ -834,7 +834,7 @@
 
   std::vector<cert> certs;
   
-  transaction_guard guard(app.db);
+  transaction_guard guard(app.db, false);
   
   revision_id rid(idx(args, 0)());
   N(app.db.revision_exists(rid), F("No such revision %s") % rid);
@@ -1331,7 +1331,7 @@
                                      std::vector<std::string> > > items;
   if (app.db.database_specified())
     {
-      transaction_guard guard(app.db);
+      transaction_guard guard(app.db, false);
       app.db.get_key_ids("", dbkeys);
       guard.commit();
     }
========================================================================
--- commands.cc	002c7e8b171019ed9c19cb1f15dcfebdec5c1257
+++ commands.cc	e91738f6920ce61beca85f8703a8efbab058a53e
@@ -523,7 +523,7 @@
 
   vector<cert> certs;
   
-  transaction_guard guard(app.db);
+  transaction_guard guard(app.db, false);
   
   revision_id ident;
   complete(app, idx(args, 0)(), ident);
@@ -626,7 +626,7 @@
 
   if (app.db.database_specified())
     {
-      transaction_guard guard(app.db);
+      transaction_guard guard(app.db, false);
       app.db.get_key_ids(pattern, pubs);
       guard.commit();
     }
@@ -1363,7 +1363,7 @@
   if (app.revision_selectors.size() == 0)
     app.require_working_copy();
 
-  transaction_guard guard(app.db);
+  transaction_guard guard(app.db, false);
 
   file_id ident;
   revision_id rid;
========================================================================
--- database.cc	7fbf000b889c6a9e67179e405279c17c08f8b1ff
+++ database.cc	d2b9a3f2fb7aae0006bd60e1266f0d9e7f882bfd
@@ -675,10 +675,20 @@
 }
 
 void 
-database::begin_transaction() 
+database::begin_transaction(bool exclusive) 
 {
   if (transaction_level == 0)
-    execute("BEGIN EXCLUSIVE");
+    {
+      if (exclusive)
+        execute("BEGIN EXCLUSIVE");
+      else
+        execute("BEGIN DEFERRED");
+      transaction_exclusive = exclusive;
+    }
+  else
+    {
+      E(!exclusive || transaction_exclusive, F("Attempt to start exclusive transaction within non-exclusive transaction."));
+    }
   transaction_level++;
 }
 
@@ -2549,10 +2559,11 @@
 
 // transaction guards
 
-transaction_guard::transaction_guard(database & d) : committed(false), db(d) 
+transaction_guard::transaction_guard(database & d, bool exclusive) : committed(false), db(d) 
 {
-  db.begin_transaction();
+  db.begin_transaction(exclusive);
 }
+
 transaction_guard::~transaction_guard()
 {
   if (committed)
@@ -2567,6 +2578,8 @@
   committed = true;
 }
 
+
+
 // called to avoid foo.db-journal files hanging around if we exit cleanly
 // without unwinding the stack (happens with SIGINT & SIGTERM)
 void
========================================================================
--- database.hh	5e52b0b84dd9cdcd155ee9af48481f8476ac2d8b
+++ database.hh	a25c05b9b4ae523a61d846f7d21817cde40580bb
@@ -88,6 +88,7 @@
   struct sqlite3 * __sql;
   struct sqlite3 * sql(bool init = false);
   int transaction_level;
+  bool transaction_exclusive;
 
   void install_functions(app_state * app);
   void install_views();
@@ -188,7 +189,7 @@
                  std::vector<cert> & certs,
                  std::string const & table);
 
-  void begin_transaction();
+  void begin_transaction(bool exclusive);
   void commit_transaction();
   void rollback_transaction();
   friend class transaction_guard;
@@ -451,12 +452,21 @@
 // transaction-protected, and it'll make sure the db aborts a
 // txn if there's any exception before you call commit()
 
+// by default, locks the database exclusively.
+// if the transaction is intended to be read-only, call with exclusive=False
+// in this case, if a database update is attempted and another process is accessing
+// the database an exception will be thrown - uglier and more confusing for the user -
+// however no data inconsistency should result.
+// 
+// an exception is thrown if an exclusive transaction_guard is created while 
+// a non-exclusive transaction_guard exists.
+
 class transaction_guard
 {
   bool committed;
   database & db;
 public:
-  transaction_guard(database & d);
+  transaction_guard(database & d, bool exclusive=true);
   ~transaction_guard();
   void commit();
 };