imap: IDLE now sends "Still here" notifications to same user's connections at the...

Perhaps this will save some battery power with mobile clients that open
multiple connections.

--HG--
branch : HEAD

diff --git a/src/imap/cmd-idle.c b/src/imap/cmd-idle.c
index 6574bd67e378c9a2c9ff5020b2ae400cf814d1cd..56507299d2892a74be70ec434ee92907f3e5206f 100644 (file)
--- a/src/imap/cmd-idle.c
+++ b/src/imap/cmd-idle.c
@@ -4,6 +4,7 @@
 #include "ioloop.h"
 #include "istream.h"
 #include "ostream.h"
+#include "crc32.h"
 #include "mail-storage-settings.h"
 #include "imap-commands.h"
 #include "imap-sync.h"
@@ -21,6 +22,7 @@ struct cmd_idle_context {
        unsigned int sync_pending:1;
 };
 
+static void idle_add_keepalive_timeout(struct cmd_idle_context *ctx);
 static bool cmd_idle_continue(struct client_command_context *cmd);
 
 static void
@@ -108,6 +110,8 @@ static void keepalive_timeout(struct cmd_idle_context *ctx)
           several clients that really want to IDLE forever and there's not
           much harm in letting them do so. */
        timeout_reset(ctx->client->to_idle);
+       /* recalculate time for the next keepalive timeout */
+       idle_add_keepalive_timeout(ctx);
 }
 
 static void idle_sync_now(struct mailbox *box, struct cmd_idle_context *ctx)
@@ -129,6 +133,22 @@ static void idle_callback(struct mailbox *box, struct cmd_idle_context *ctx)
        }
 }
 
+static void idle_add_keepalive_timeout(struct cmd_idle_context *ctx)
+{
+       unsigned int interval = ctx->client->set->imap_idle_notify_interval;
+
+       if (interval == 0)
+               return;
+
+       interval -= (time(NULL) +
+                    crc32_str(ctx->client->user->username)) % interval;
+
+       if (ctx->keepalive_to != NULL)
+               timeout_remove(&ctx->keepalive_to);
+       ctx->keepalive_to = timeout_add(interval * 1000,
+                                       keepalive_timeout, ctx);
+}
+
 static bool cmd_idle_continue(struct client_command_context *cmd)
 {
        struct client *client = cmd->client;
@@ -166,7 +186,7 @@ static bool cmd_idle_continue(struct client_command_context *cmd)
        }
        if (client->output->offset != orig_offset &&
            ctx->keepalive_to != NULL)
-               timeout_reset(ctx->keepalive_to);
+               idle_add_keepalive_timeout(ctx);
 
        if (ctx->sync_pending) {
                /* more changes occurred while we were sending changes to
@@ -204,10 +224,7 @@ bool cmd_idle(struct client_command_context *cmd)
        ctx = p_new(cmd->pool, struct cmd_idle_context, 1);
        ctx->cmd = cmd;
        ctx->client = client;
-
-       ctx->keepalive_to = client->set->imap_idle_notify_interval == 0 ? NULL :
-               timeout_add(client->set->imap_idle_notify_interval * 1000,
-                           keepalive_timeout, ctx);
+       idle_add_keepalive_timeout(ctx);
 
        if (client->mailbox != NULL) {
                const struct mail_storage_settings *set;