From c8bff8ac923645d517183b130158d61f85540b33 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Sat, 10 Mar 2012 12:32:32 +0000
Subject: [PATCH] daemon: Implement 'test_variables'.

This is the same as 'set_variables', but it doesn't update the state.
It just returns the names of the jobs that *would* run if these
variables were set.
---
 daemon/daemon.ml | 48 ++++++++++++++++++++++++++++++++++++++++++++----
 lib/whenproto.x  |  1 +
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/daemon/daemon.ml b/daemon/daemon.ml
index d9393e7..5b9fc3b 100644
--- a/daemon/daemon.ml
+++ b/daemon/daemon.ml
@@ -81,6 +81,7 @@ let rec init j d =
       ~proc_get_job
       ~proc_set_variables
       ~proc_get_job_names
+      ~proc_test_variables
       (Rpc_server.Unix addr)
       Rpc.Tcp (* not TCP, this is the same as SOCK_STREAM *)
       Rpc.Socket
@@ -110,7 +111,8 @@ and proc_set_variable (name, value) =
 
     (* Which jobs need to be re-evaluated? *)
     let jobs = Whenstate.get_dependencies !state [name] in
-    let state' = reevaluate_whenjobs !state jobs in
+    let jobnames, state' = reevaluate_whenjobs !state jobs in
+    let state' = run_whenjobs state' jobnames in
     state := state';
 
     `ok
@@ -210,7 +212,8 @@ and proc_set_variables vars =
 
     (* Which jobs need to be re-evaluated? *)
     let jobs = Whenstate.get_dependencies !state (List.map fst vars) in
-    let state' = reevaluate_whenjobs !state jobs in
+    let jobnames, state' = reevaluate_whenjobs !state jobs in
+    let state' = run_whenjobs state' jobnames in
     state := state';
 
     `ok
@@ -220,6 +223,39 @@ and proc_set_variables vars =
 and proc_get_job_names () =
   Array.of_list (Whenstate.get_job_names !state)
 
+and proc_test_variables vars =
+  (* This is the same as proc_set_variables, except that it doesn't
+   * update the state, it just returns the jobs that *would* run if
+   * these variables were set to these values.
+   *)
+  let vars = Array.map (
+    fun { Whenproto_aux.sv_name = name; sv_value = value } ->
+      name, variable_of_rpc value
+  ) vars in
+  let vars = Array.to_list vars in
+
+  if !debug then
+    Syslog.notice "remote call: test_variables (%s)"
+      (String.concat " "
+         (List.map (
+           fun (name, value) ->
+             sprintf "%s=%s" name (string_of_variable value)
+          ) vars));
+
+  List.iter (fun (name, _) -> check_valid_variable_name name) vars;
+
+  (* Update all the variables atomically. *)
+  let state = List.fold_left (
+    fun s (name, value) -> Whenstate.set_variable s name value
+  ) !state vars in
+
+  (* Which jobs WOULD be re-evaluated? *)
+  let jobs = Whenstate.get_dependencies state (List.map fst vars) in
+  let jobnames, _ = reevaluate_whenjobs state jobs in
+
+  (* Return the names. *)
+  Array.of_list jobnames
+
 (* Reload the jobs file. *)
 and reload_file () =
   let file = sprintf "%s/jobs.cmo" !jobsdir in
@@ -250,14 +286,16 @@ and reload_file () =
 
   (* Re-evaluate all when jobs. *)
   let jobs = Whenstate.get_whenjobs !state in
-  let state' = reevaluate_whenjobs ~onload:true !state jobs in
+  let jobnames, state' = reevaluate_whenjobs ~onload:true !state jobs in
+  let state' = run_whenjobs state' jobnames in
   state := state';
 
   (* Schedule the next every job to run. *)
   schedule_next_everyjob ()
 
 (* Re-evaluate each when-statement job, in a loop until we reach
- * a fixpoint.  Run the jobs and return the updated state.
+ * a fixpoint.  Return the list of job names that should run and
+ * the updated state.
  *)
 and reevaluate_whenjobs ?onload state jobs =
   let rec loop (set, state) jobs =
@@ -287,7 +325,9 @@ and reevaluate_whenjobs ?onload state jobs =
 
   (* Ensure the jobs always run in predictable (name) order. *)
   let jobnames = List.sort compare_jobnames jobnames in
+  jobnames, state
 
+and run_whenjobs state jobnames =
   (* Run the jobs. *)
   let jobs = List.map (Whenstate.get_job state) jobnames in
   List.fold_left run_job state jobs
diff --git a/lib/whenproto.x b/lib/whenproto.x
index 93173cf..1d8980a 100644
--- a/lib/whenproto.x
+++ b/lib/whenproto.x
@@ -101,5 +101,6 @@ program When {
     job get_job (string_big_int) = 9;
     status set_variables (set_variable_list) = 10;
     job_name_list get_job_names (void) = 11;
+    job_name_list test_variables (set_variable_list) = 12;
   } = 1;
 } = 0x20008081;
-- 
1.8.3.1