From d5b5529d765513b49b9bb2a75bc3a02cfd944a60 Mon Sep 17 00:00:00 2001
From: Timo Sirainen <tss@iki.fi>
Date: Fri, 1 Oct 2010 16:39:11 +0100
Subject: [PATCH] pop3: Added pop3_fast_size_lookups setting.

---
 doc/example-config/conf.d/20-pop3.conf |  7 +++++
 src/pop3/pop3-client.c                 | 41 +++++++++++++++++++++++++-
 src/pop3/pop3-settings.c               |  2 ++
 src/pop3/pop3-settings.h               |  1 +
 4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/doc/example-config/conf.d/20-pop3.conf b/doc/example-config/conf.d/20-pop3.conf
index 1b32fda753..3559b9a7b0 100644
--- a/doc/example-config/conf.d/20-pop3.conf
+++ b/doc/example-config/conf.d/20-pop3.conf
@@ -19,6 +19,13 @@ protocol pop3 {
   # Keep the mailbox locked for the entire POP3 session.
   #pop3_lock_session = no
 
+  # POP3 requires message sizes to be listed as if they had CR+LF linefeeds.
+  # Many POP3 servers violate this by returning the sizes with LF linefeeds,
+  # because it's faster to get. When this setting is enabled, Dovecot still
+  # tries to do the right thing first, but if that requires opening the
+  # message, it fallbacks to the easier (but incorrect) size.
+  #pop3_fast_size_lookups = no
+
   # POP3 UIDL (unique mail identifier) format to use. You can use following
   # variables, along with the variable modifiers described in
   # doc/wiki/Variables.txt (e.g. %Uf for the filename in uppercase)
diff --git a/src/pop3/pop3-client.c b/src/pop3/pop3-client.c
index 7baf191670..cfb125134b 100644
--- a/src/pop3/pop3-client.c
+++ b/src/pop3/pop3-client.c
@@ -64,6 +64,45 @@ static void client_idle_timeout(struct client *client)
 	}
 }
 
+static int
+pop3_mail_get_size(struct client *client, struct mail *mail, uoff_t *size_r)
+{
+	struct mail_storage *storage;
+	enum mail_error error;
+	int ret;
+
+	if (!client->set->pop3_fast_size_lookups)
+		return mail_get_virtual_size(mail, size_r);
+
+	/* first try to get the virtual size */
+	mail->lookup_abort = MAIL_LOOKUP_ABORT_READ_MAIL;
+	ret = mail_get_virtual_size(mail, size_r);
+	mail->lookup_abort = MAIL_LOOKUP_ABORT_NEVER;
+	if (ret == 0)
+		return 0;
+
+	storage = mailbox_get_storage(mail->box);
+	(void)mail_storage_get_last_error(storage, &error);
+	if (error != MAIL_ERROR_NOTPOSSIBLE)
+		return -1;
+
+	/* virtual size not available with a fast lookup.
+	   fallback to trying the physical size */
+	mail->lookup_abort = MAIL_LOOKUP_ABORT_READ_MAIL;
+	ret = mail_get_physical_size(mail, size_r);
+	mail->lookup_abort = MAIL_LOOKUP_ABORT_NEVER;
+	if (ret == 0)
+		return 0;
+
+	(void)mail_storage_get_last_error(storage, &error);
+	if (error != MAIL_ERROR_NOTPOSSIBLE)
+		return -1;
+
+	/* no way to quickly get the size. fallback to doing a slow virtual
+	   size lookup */
+	return mail_get_virtual_size(mail, size_r);
+}
+
 static int read_mailbox(struct client *client, uint32_t *failed_uid_r)
 {
         struct mailbox_status status;
@@ -94,7 +133,7 @@ static int read_mailbox(struct client *client, uint32_t *failed_uid_r)
 
 	mail = mail_alloc(t, MAIL_FETCH_VIRTUAL_SIZE, NULL);
 	while (mailbox_search_next(ctx, mail)) {
-		if (mail_get_virtual_size(mail, &size) < 0) {
+		if (pop3_mail_get_size(client, mail, &size) < 0) {
 			ret = mail->expunged ? 0 : -1;
 			*failed_uid_r = mail->uid;
 			break;
diff --git a/src/pop3/pop3-settings.c b/src/pop3/pop3-settings.c
index 0fa239f6ca..b6e3843aa8 100644
--- a/src/pop3/pop3-settings.c
+++ b/src/pop3/pop3-settings.c
@@ -68,6 +68,7 @@ static const struct setting_define pop3_setting_defines[] = {
 	DEF(SET_BOOL, pop3_reuse_xuidl),
 	DEF(SET_BOOL, pop3_save_uidl),
 	DEF(SET_BOOL, pop3_lock_session),
+	DEF(SET_BOOL, pop3_fast_size_lookups),
 	DEF(SET_STR, pop3_client_workarounds),
 	DEF(SET_STR, pop3_logout_format),
 
@@ -83,6 +84,7 @@ static const struct pop3_settings pop3_default_settings = {
 	.pop3_reuse_xuidl = FALSE,
 	.pop3_save_uidl = FALSE,
 	.pop3_lock_session = FALSE,
+	.pop3_fast_size_lookups = FALSE,
 	.pop3_client_workarounds = "",
 	.pop3_logout_format = "top=%t/%p, retr=%r/%b, del=%d/%m, size=%s"
 };
diff --git a/src/pop3/pop3-settings.h b/src/pop3/pop3-settings.h
index 43c148b586..174e2ba4ba 100644
--- a/src/pop3/pop3-settings.h
+++ b/src/pop3/pop3-settings.h
@@ -20,6 +20,7 @@ struct pop3_settings {
 	bool pop3_reuse_xuidl;
 	bool pop3_save_uidl;
 	bool pop3_lock_session;
+	bool pop3_fast_size_lookups;
 	const char *pop3_client_workarounds;
 	const char *pop3_logout_format;
 
-- 
2.47.3