From 01329bdf82e932acfb5b228851177123509850b7 Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <ossi@users.sf.net>
Date: Mon, 4 Apr 2022 21:41:18 +0200
Subject: [PATCH] exclude placeholders from trashing

it makes no sense to trash the placeholders, and in fact the common
case is that they are deleted due to being replaced by the full
message.

a separate S_PURGED state needed to be added, as S_PURGE needs to be
reset after setting F_DELETED (so the operation doesn't count as still
pending after journal replay), yet trashing needs an indicator. logging
is now done via a separate command, as piggy-backing it on flag updates
just makes things less legible for no benefit.

this is mostly academical, as trashing being done on the side where
placeholders reside is rather unlikely.
---
 src/run-tests.pl | 32 +++++++++++++++++++++++++++++---
 src/sync.c       | 16 +++++++++++++++-
 src/sync_p.h     |  1 +
 src/sync_state.c |  8 ++++++--
 4 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/src/run-tests.pl b/src/run-tests.pl
index 72c8133..00959c1 100755
--- a/src/run-tests.pl
+++ b/src/run-tests.pl
@@ -605,10 +605,14 @@ sub cmptrash($$$)
 			print STDERR "Missing message $bn:".mn($num)."\n";
 			$ret = 1;
 		}
+		if ($ph) {
+			print STDERR "Message $bn:".mn($num)." is placeholder\n";
+			$ret = 1;
+		}
 	}
 	for my $num (sort { $a <=> $b } keys %$ms) {
 		if (!defined($$ref_ms{$num})) {
-			print STDERR "Excess message $bn:".mn($num)."\n";
+			print STDERR "Excess message $bn:".mn($num).($$ms{$num} ? " (is placeholder)" : "")."\n";
 			$ret = 1;
 		}
 	}
@@ -1057,7 +1061,7 @@ my @X22 = (
   B, "", ">->", "^*",
   B, "", "", "&1/",
   C, "^F*", "<-<+F", "",
-  C, "&1+T", "^T", "&",
+  C, "&1+T", "^", "&",
 );
 test("max size + flagging", \@x22, \@X22, \@O21);
 
@@ -1145,12 +1149,16 @@ test("max messages + expunge", \@x38, \@X38, \@O38);
 # Trashing
 
 my @x10 = (
-  E, A, E,
+  K, A, K,
   A, "*", "*~", "*T",
   B, "*T", "*^", "",
   C, "*T", "*", "*T",
   D, "_", "*", "*",
   E, "*", "*", "_",
+  F, "**", "*>", "*T?",
+  G, "*T?", "*<", "**",
+  J, "**", "*>", "*F?",
+  K, "*F?", "*<", "**",
   L, "*T", "", "",
   M, "", "", "*T",
   R, "", "", "*",  # Force maxuid in the interrupt-resume test.
@@ -1166,6 +1174,12 @@ my @X11 = (
   C, "#/", "/", "#/",
   D, "", "/", "#/",
   E, "#/", "/", "",
+  F, "#/", "/", "/",
+  G, "/", "/", "#/",
+  J, "", ">->", "^*",
+  J, "", "", "&1/",
+  K, "^*", "<-<", "",
+  K, "&1/", "", "",
   L, "#/", "", "",
   M, "", "", "#/",
   R, "*", "*", "",
@@ -1182,6 +1196,12 @@ my @X12 = (
   C, "#/", "/", "/",
   D, "", "/", "/",
   E, "#/", "/", "",
+  F, "#/", "/", "/",
+  G, "/", "/", "#/",
+  J, "", ">->", "^*",
+  J, "", "", "&1/",
+  K, "^*", "<-<", "",
+  K, "&1/", "", "",
   L, "#/", "", "",
   M, "", "", "#/",
   R, "*", "*", "",
@@ -1198,6 +1218,12 @@ my @X13 = (
   C, "#/", "/", "/",
   D, "", "/", "/",
   E, "#/", "/", "",
+  F, "#/", "/", "/",
+  G, "#/", "/", "/",
+  J, "", ">->", "^*",
+  J, "", "", "&1/",
+  K, "^*", "<-<", "",
+  K, "&1/", "", "",
   L, "#/", "", "",
   M, "#", "", "/",
   R, "*", "*", "",
diff --git a/src/sync.c b/src/sync.c
index ee3af7e..62c48a6 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -1498,7 +1498,10 @@ flags_set( int sts, void *aux )
 static void
 flags_set_p2( sync_vars_t *svars, sync_rec_t *srec, int t )
 {
-	if (srec->status & S_DELETE) {
+	if (srec->status & S_PURGE) {
+		JLOG( "P %u %u", (srec->uid[F], srec->uid[N]), "deleted dummy" );
+		srec->status = (srec->status & ~S_PURGE) | S_PURGED;
+	} else if (srec->status & S_DELETE) {
 		JLOG( "%c %u %u 0", ("><"[t], srec->uid[F], srec->uid[N]), "%sed deletion", str_hl[t] );
 		srec->uid[t^1] = 0;
 	} else {
@@ -1570,6 +1573,17 @@ msgs_flags_set( sync_vars_t *svars, int t )
 				debug( "is expired\n" );
 				continue;
 			}
+			if (srec->status & S_DUMMY(t)) {
+				// This is mostly academical, as trashing being done on the side
+				// where placeholders reside is rather unlikely.
+				debug( "is dummy\n" );
+				continue;
+			}
+			if (srec->status & S_PURGED) {
+				// As above.
+				debug( "is deleted dummy\n" );
+				continue;
+			}
 			if (only_new && !(srec->status & (S_PENDING | S_DUMMY(t^1) | S_SKIPPED))) {
 				debug( "is not new\n" );
 				continue;
diff --git a/src/sync_p.h b/src/sync_p.h
index 529a010..704c10c 100644
--- a/src/sync_p.h
+++ b/src/sync_p.h
@@ -21,6 +21,7 @@ BIT_ENUM(
 	S_DELETE,       // ephemeral: flags propagation is a deletion
 	S_UPGRADE,      // ephemeral: upgrading placeholder, do not apply MaxSize
 	S_PURGE,        // ephemeral: placeholder is being nuked
+	S_PURGED,       // ephemeral: placeholder was nuked
 )
 
 // This is the persistent status of the sync record, with regard to the journal.
diff --git a/src/sync_state.c b/src/sync_state.c
index 42a9a19..3f72177 100644
--- a/src/sync_state.c
+++ b/src/sync_state.c
@@ -292,6 +292,7 @@ load_state( sync_vars_t *svars )
 				case 'N':
 				case 'F':
 				case 'T':
+				case 'P':
 				case '+':
 				case '&':
 				case '-':
@@ -378,8 +379,11 @@ load_state( sync_vars_t *svars )
 					case '*':
 						debug( "flags now %u\n", t3 );
 						srec->flags = (uchar)t3;
-						srec->aflags[F] = srec->aflags[N] = 0;  // Clear F_DELETED from purge
-						srec->status &= ~S_PURGE;
+						break;
+					case 'P':
+						debug( "deleted dummy\n" );
+						srec->aflags[F] = srec->aflags[N] = 0;  // Clear F_DELETED
+						srec->status = (srec->status & ~S_PURGE) | S_PURGED;
 						break;
 					case '~':
 						srec->status = (srec->status & ~S_LOGGED) | t3;