isync

mailbox synchronization program
git clone https://git.code.sf.net/p/isync/isync
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commit 0da273686f7ca5a5be7b27cc27480b52465fea24
parent 3d90507a759e81bc5c3e116a3751f34657aa023b
Author: Oswald Buddenhagen <ossi@users.sf.net>
Date:   Fri, 17 Jun 2022 15:57:56 +0200

rework flag propagation during placeholder upgrade

don't implicitly propagate flags with upgrades. the user asked for
replacing the body, so do just that. if they also asked for flag
propagation, handle it like the case without upgrade as far as possible.
this makes async parallel flag propagation in the opposite direction
robust, while still being reasonably simple.

Diffstat:
Msrc/run-tests.pl | 16++++++++++------
Msrc/sync.c | 95+++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------
Msrc/sync_state.c | 21++++++++++++++++-----
3 files changed, 88 insertions(+), 44 deletions(-)

diff --git a/src/run-tests.pl b/src/run-tests.pl @@ -1066,20 +1066,24 @@ my @X21 = ( test("max size", \@x20, \@X21, \@O21); my @x22 = ( - C, 0, B, + E, 0, B, A, "*", "", "", - B, "**", "", "", - C, "*?", "*<", "*F*", + B, "*PR*", "", "", + C, "*PR?", "*<DP", "*DFP*", + D, "*PR?", "*<DP", "*DP*", + E, "*PR*", "*>DP", "*DP?", A, "", "*", "*", - B, "", "*>", "*F?", + B, "", "*>DP", "*DFP?", ); my @X22 = ( C, 0, B, - B, "", ">->", "^*", + B, "", ">->D+R", "^PR*", B, "", "", "&1/", - C, "^F*", "<-<+F", "", + C, "^FPR*", "<-<D+FR", "-D+R", C, "&1+T", "^", "&", + D, "", "-D+R", "-D+R", + E, "", "-D+R", "-D+R", ); test("max size + flagging", \@x22, \@X22, \@O21); diff --git a/src/sync.c b/src/sync.c @@ -289,12 +289,21 @@ msg_fetched( int sts, void *aux ) return; } - vars->data.flags = sanitize_flags( vars->data.flags, svars, t ); - if (srec && !(srec->status & S_UPGRADE)) { - if (vars->data.flags) { - srec->pflags = vars->data.flags; - JLOG( "%% %u %u %u", (srec->uid[F], srec->uid[N], srec->pflags), - "%sing with flags %s", (str_hl[t], fmt_lone_flags( srec->pflags ).str) ); + if (srec && (srec->status & S_UPGRADE)) { + vars->data.flags = (srec->pflags | srec->aflags[t]) & ~srec->dflags[t]; + if (srec->aflags[t] || srec->dflags[t]) { + JLOG( "$ %u %u %u %u", (srec->uid[F], srec->uid[N], srec->aflags[t], srec->dflags[t]), + "%sing upgrade with flags: +%s -%s", + (str_hl[t], fmt_flags( srec->aflags[t] ).str, fmt_flags( srec->dflags[t] ).str) ); + } + } else { + vars->data.flags = sanitize_flags( vars->data.flags, svars, t ); + if (srec) { + if (vars->data.flags) { + srec->pflags = vars->data.flags; + JLOG( "%% %u %u %u", (srec->uid[F], srec->uid[N], srec->pflags), + "%sing with flags %s", (str_hl[t], fmt_lone_flags( srec->pflags ).str) ); + } } } @@ -1008,7 +1017,23 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux for (t = 0; t < 2; t++) { if (srec->msg[t] && (srec->msg[t]->flags & F_DELETED)) srec->status |= S_DEL(t); - if (del[t]) { + if (srec->status & S_UPGRADE) { + // Such records hold orphans by definition, so the del[] cases are irrelevant. + if (srec->uid[t]) { + // Direction towards the source message. + // The placeholder was already detached, so use its saved flags instead. + sflags = srec->pflags; + goto doflags; + } + // Direction towards the copy. + if (srec->msg[t^1]) { + // Flag propagation along placeholder upgrades must be explicitly requested, + // and is, at the source, handled like any other flag update. + sflags = srec->msg[t^1]->flags; + goto doflags; + } + debug( " no %s\n", str_fn[t^1] ); + } else if (del[t]) { // The target was newly expunged, so there is nothing to update. // The deletion is propagated in the opposite iteration. } else if (!srec->uid[t]) { @@ -1044,8 +1069,11 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux debug( " no %s\n", str_fn[t^1] ); } else { // We have a source. The target may be in an unknown state. + sflags = srec->msg[t^1]->flags; + + doflags: if (svars->chan->ops[t] & OP_FLAGS) { - sflags = sanitize_flags( srec->msg[t^1]->flags, svars, t ); + sflags = sanitize_flags( sflags, svars, t ); if ((t == F) && (srec->status & (S_EXPIRE|S_EXPIRED))) { /* Don't propagate deletion resulting from expiration. */ debug( " near side expiring\n" ); @@ -1076,32 +1104,15 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux ushort suflags = srec->msg[N] ? srec->msg[N]->flags : 0; if ((muflags | suflags) & F_FLAGGED) { t = (srec->status & S_DUMMY(F)) ? F : N; - // We calculate the flags for the replicated message already now, - // because after an interruption the dummy may be already gone. - srec->pflags = ((srec->msg[t]->flags & ~(F_SEEN|F_FLAGGED)) | srec->aflags[t]) & ~srec->dflags[t]; - // Consequently, the srec's flags are committed right away as well. - srec->flags = (srec->flags | srec->aflags[t]) & ~srec->dflags[t]; - JLOG( "^ %u %u %u %u", (srec->uid[F], srec->uid[N], srec->pflags, srec->flags), - "upgrading %s placeholder, dummy's flags %s, srec flags %s", - (str_fn[t], fmt_lone_flags( srec->pflags ).str, fmt_lone_flags( srec->flags ).str) ); + // We save away the dummy's flags, because after an + // interruption it may be already gone. Filtering as above. + srec->pflags = srec->msg[t]->flags & ~(F_SEEN | F_FLAGGED); + JLOG( "^ %u %u %u", (srec->uid[F], srec->uid[N], srec->pflags), + "upgrading %s placeholder, dummy's flags %s", + (str_fn[t], fmt_lone_flags( srec->pflags ).str) ); nsrec = upgrade_srec( svars, srec, t ); } } - // This is separated, because the upgrade can come from the journal. - if (srec->status & S_UPGRADE) { - t = !srec->uid[F] ? F : N; - tmsg = srec->msg[t^1]; - if ((svars->chan->ops[t] & OP_EXPUNGE) && (srec->pflags & F_DELETED)) { - JLOG( "- %u %u", (srec->uid[F], srec->uid[N]), "killing upgrade - would be expunged anyway" ); - tmsg->srec = NULL; - srec->status = S_DEAD; - } else { - // Pretend that the source message has the adjusted flags of the dummy. - tmsg->flags = srec->pflags; - tmsg->status |= M_FLAGS; - any_new[t] = 1; - } - } srec = nsrec; // Minor optimization: skip freshly created placeholder entry. } } @@ -1136,12 +1147,30 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux "was previously skipped" ); } } else { - if (!(svars->chan->ops[t] & OP_NEW)) + if (!(svars->chan->ops[t] & OP_NEW) && !(srec->status & S_UPGRADE)) continue; if (!(srec->status & S_PENDING)) continue; // Nothing to do - the message is paired or expired // Propagation was scheduled, but we got interrupted debug( "unpropagated old message %u\n", tmsg->uid ); + + if (srec->status & S_UPGRADE) { + if ((svars->chan->ops[t] & OP_EXPUNGE) && + ((srec->pflags | srec->aflags[t]) & ~srec->dflags[t] & F_DELETED)) { + // We can't just kill the entry, as we may be propagating flags + // (in particular, F_DELETED) towards the real message. + // No dummy is actually present, but pretend there is, so the + // real message is considered new when trashing. + srec->status = (srec->status & ~(S_PENDING | S_UPGRADE)) | S_DUMMY(t); + JLOG( "~ %u %u %d", (srec->uid[F], srec->uid[N], srec->status & S_LOGGED), + "canceling placeholder upgrade - would be expunged anyway" ); + continue; + } + // Prevent the driver from "completing" the flags, as we'll ignore them anyway. + tmsg->status |= M_FLAGS; + any_new[t] = 1; + continue; + } } } else { // The 1st unknown message which should be known marks the end @@ -1183,7 +1212,7 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux continue; } if (!(tmsg->flags & F_FLAGGED) && tmsg->size > svars->chan->stores[t]->max_size && - !(srec->status & (S_DUMMY(F) | S_DUMMY(N) | S_UPGRADE))) { + !(srec->status & (S_DUMMY(F) | S_DUMMY(N)))) { srec->status |= S_DUMMY(t); JLOG( "_ %u %u", (srec->uid[F], srec->uid[N]), "placeholder only - too big" ); } diff --git a/src/sync_state.c b/src/sync_state.c @@ -308,9 +308,10 @@ load_state( sync_vars_t *svars ) case '*': case '%': case '~': + case '^': bad = sscanf( buf + 2, "%u %u %u", &t1, &t2, &t3 ) != 3; break; - case '^': + case '$': bad = sscanf( buf + 2, "%u %u %u %u", &t1, &t2, &t3, &t4 ) != 4; break; default: @@ -411,11 +412,17 @@ load_state( sync_vars_t *svars ) case '^': tn = (srec->status & S_DUMMY(F)) ? F : N; srec->pflags = (uchar)t3; - srec->flags = (uchar)t4; - debug( "upgrading %s placeholder, dummy's flags %s, srec flags %s\n", - str_fn[tn], fmt_lone_flags( t3 ).str, fmt_lone_flags( t4 ).str ); + debug( "upgrading %s placeholder, dummy's flags %s\n", + str_fn[tn], fmt_lone_flags( t3 ).str ); srec = upgrade_srec( svars, srec, tn ); break; + case '$': + tn = !srec->uid[F] ? F : N; + srec->aflags[tn] = (uchar)t3; + srec->dflags[tn] = (uchar)t4; + debug( "flag update for %s now +%s -%s\n", + str_fn[tn], fmt_flags( t3 ).str, fmt_flags( t4 ).str ); + break; default: assert( !"Unhandled journal entry" ); } @@ -522,8 +529,12 @@ assign_uid( sync_vars_t *svars, sync_rec_t *srec, int t, uint uid ) if (uid == svars->newmaxuid[t] + 1) svars->newmaxuid[t] = uid; if (uid) { - if (!(srec->status & S_UPGRADE)) + if (srec->status & S_UPGRADE) { + srec->flags = (srec->flags | srec->aflags[t]) & ~srec->dflags[t]; + srec->aflags[t] = srec->dflags[t] = 0; // Cleanup after journal replay + } else { srec->flags = srec->pflags; + } } srec->status &= ~(S_PENDING | S_UPGRADE); srec->tuid[0] = 0;