global: start relying on buffer_free(NULL) being a no-op

Cleanup performed with the following semantic patch:

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	buffer_free(&E);
	- }
	+ buffer_free(&E);

src/lib-compression/istream-lz4.c

@@ -29,8 +29,7 @@ static void i_stream_lz4_close(struct iostream_private *stream,
 {
 	struct lz4_istream *zstream = (struct lz4_istream *)stream;
 
-	if (zstream->chunk_buf != NULL)
-		buffer_free(&zstream->chunk_buf);
+	buffer_free(&zstream->chunk_buf);
 	if (close_parent)
 		i_stream_close(zstream->istream.parent);
 }

src/lib-dcrypt/istream-decrypt.c

@@ -836,8 +836,7 @@ void i_stream_decrypt_destroy(struct iostream_private *stream)
 	struct decrypt_istream *dstream =
 		(struct decrypt_istream *)stream;
 
-	if (dstream->buf != NULL)
-		buffer_free(&dstream->buf);
+	buffer_free(&dstream->buf);
 	if (dstream->iv != NULL)
 		i_free_and_null(dstream->iv);
 	if (dstream->ctx_sym != NULL)

src/lib-fts/fts-tokenizer.c

@@ -121,8 +121,7 @@ void fts_tokenizer_unref(struct fts_tokenizer **_tok)
 	if (--tok->refcount > 0)
 		return;
 
-	if (tok->parent_input != NULL)
-		buffer_free(&tok->parent_input);
+	buffer_free(&tok->parent_input);
 	if (tok->parent != NULL)
 		fts_tokenizer_unref(&tok->parent);
 	tok->v->destroy(tok);

src/lib-imap-urlauth/imap-urlauth-connection.c

@@ -973,8 +973,7 @@ static void imap_urlauth_connection_disconnect
 		conn->literal_fd = -1;
 	}
 
-	if (conn->literal_buf != NULL)
-		buffer_free(&conn->literal_buf);
+	buffer_free(&conn->literal_buf);
 	timeout_remove(&conn->to_reconnect);
 	timeout_remove(&conn->to_idle);
 	imap_urlauth_stop_response_timeout(conn);

src/lib-index/mail-cache-transaction.c

@@ -156,8 +156,7 @@ void mail_cache_transaction_rollback(struct mail_cache_transaction_ctx **_ctx)
 	ctx->view->trans_seq1 = ctx->view->trans_seq2 = 0;
 
 	mail_index_view_close(&ctx->view->trans_view);
-	if (ctx->cache_data != NULL)
-		buffer_free(&ctx->cache_data);
+	buffer_free(&ctx->cache_data);
 	if (array_is_created(&ctx->cache_data_seq))
 		array_free(&ctx->cache_data_seq);
 	if (array_is_created(&ctx->cache_data_wanted_seqs))

src/lib-index/mail-cache.c

@@ -587,8 +587,7 @@ void mail_cache_free(struct mail_cache **_cache)
 	mail_index_unregister_expunge_handler(cache->index, cache->ext_id);
 	mail_cache_file_close(cache);
 
-	if (cache->read_buf != NULL)
-		buffer_free(&cache->read_buf);
+	buffer_free(&cache->read_buf);
 	hash_table_destroy(&cache->field_name_hash);
 	pool_unref(&cache->field_pool);
 	i_free(cache->field_file_map);

src/lib-index/mail-index-sync-update.c

@@ -839,8 +839,7 @@ void mail_index_sync_map_deinit(struct mail_index_sync_map_ctx *sync_map_ctx)
 {
 	i_assert(sync_map_ctx->modseq_ctx == NULL);
 
-	if (sync_map_ctx->unknown_extensions != NULL)
-		buffer_free(&sync_map_ctx->unknown_extensions);
+	buffer_free(&sync_map_ctx->unknown_extensions);
 	if (sync_map_ctx->expunge_handlers_used)
 		mail_index_sync_deinit_expunge_handlers(sync_map_ctx);
 	mail_index_sync_deinit_handlers(sync_map_ctx);

src/lib-index/mail-index-transaction-update.c

@@ -76,10 +76,8 @@ void mail_index_transaction_reset_v(struct mail_index_transaction *t)
 		array_free(&t->ext_reset_ids);
 	if (array_is_created(&t->ext_reset_atomic))
 		array_free(&t->ext_reset_atomic);
-	if (t->attribute_updates != NULL)
-		buffer_free(&t->attribute_updates);
-	if (t->attribute_updates_suffix != NULL)
-		buffer_free(&t->attribute_updates_suffix);
+	buffer_free(&t->attribute_updates);
+	buffer_free(&t->attribute_updates_suffix);
 
 	t->first_new_seq = mail_index_view_get_messages_count(t->view)+1;
 	t->last_new_seq = 0;

src/lib-index/mail-index-transaction-view.c

@@ -35,8 +35,7 @@ static void tview_close(struct mail_index_view *view)
 
 	if (tview->lookup_map != NULL)
 		mail_index_unmap(&tview->lookup_map);
-	if (tview->lookup_return_data != NULL)
-		buffer_free(&tview->lookup_return_data);
+	buffer_free(&tview->lookup_return_data);
 
 	if (array_is_created(&tview->all_recs)) {
 		recs = array_get_modifiable(&tview->all_recs, &count);

src/lib-index/mail-transaction-log-file.c

@@ -114,8 +114,7 @@ void mail_transaction_log_file_free(struct mail_transaction_log_file **_file)
 	if (file == file->log->head)
 		file->log->head = NULL;
 
-	if (file->buffer != NULL) 
-		buffer_free(&file->buffer);
+	buffer_free(&file->buffer);
 
 	if (file->mmap_base != NULL) {
 		if (munmap(file->mmap_base, file->mmap_size) < 0)
@@ -957,8 +956,7 @@ int mail_transaction_log_file_open(struct mail_transaction_log_file *file,
 		}
 
 		/* ESTALE - try again */
-		if (file->buffer != NULL)
-			buffer_free(&file->buffer);
+		buffer_free(&file->buffer);
         }
 
 	mail_transaction_log_file_add_to_list(file);
@@ -1733,10 +1731,9 @@ static int
 mail_transaction_log_file_mmap(struct mail_transaction_log_file *file,
 			       const char **reason_r)
 {
-	if (file->buffer != NULL) {
-		/* in case we just switched to mmaping */
-		buffer_free(&file->buffer);
-	}
+	/* we may have switched to mmaping */
+	buffer_free(&file->buffer);
+
 	file->mmap_size = file->last_size;
 	file->mmap_base = mmap(NULL, file->mmap_size, PROT_READ, MAP_SHARED,
 			       file->fd, 0);

src/lib-mail/istream-attachment-extractor.c

@@ -538,8 +538,7 @@ static void astream_part_reset(struct attachment_istream *astream)
 
 	i_free_and_null(part->content_type);
 	i_free_and_null(part->content_disposition);
-	if (part->part_buf != NULL)
-		buffer_free(&part->part_buf);
+	buffer_free(&part->part_buf);
 
 	i_zero(part);
 	part->temp_fd = -1;

src/lib-mail/istream-qp-decoder.c

@@ -21,8 +21,7 @@ static void i_stream_qp_decoder_close(struct iostream_private *stream,
 
 	if (bstream->qp != NULL)
 		qp_decoder_deinit(&bstream->qp);
-	if (bstream->buf != NULL)
-		buffer_free(&bstream->buf);
+	buffer_free(&bstream->buf);
 	if (close_parent)
 		i_stream_close(bstream->istream.parent);
 }

src/lib-mail/istream-qp-encoder.c

@@ -21,8 +21,7 @@ static void i_stream_qp_encoder_close(struct iostream_private *stream,
 
 	if (bstream->qp != NULL)
 		qp_encoder_deinit(&bstream->qp);
-	if (bstream->buf != NULL)
-		buffer_free(&bstream->buf);
+	buffer_free(&bstream->buf);
 	if (close_parent)
 		i_stream_close(bstream->istream.parent);
 }

src/lib-mail/message-header-decode.c

@@ -132,8 +132,7 @@ void message_header_decode(const unsigned char *data, size_t size,
 		(void)callback(data + start_pos, size - start_pos,
 			       NULL, context);
 	}
-	if (decodebuf != NULL)
-		buffer_free(&decodebuf);
+	buffer_free(&decodebuf);
 }
 
 struct decode_utf8_context {

src/lib-mail/test-istream-attachment.c

@@ -313,8 +313,7 @@ static int test_input_stream(struct istream *file_input)
 	}
 
 	buffer_free(&base_buf);
-	if (attachment_data != NULL)
-		buffer_free(&attachment_data);
+	buffer_free(&attachment_data);
 	if (array_is_created(&attachments))
 		array_free(&attachments);
 	return ret;
@@ -357,8 +356,7 @@ static void test_istream_attachment(void)
 	i_stream_unref(&input);
 	i_stream_unref(&datainput);
 
-	if (attachment_data != NULL)
-		buffer_free(&attachment_data);
+	buffer_free(&attachment_data);
 	if (array_is_created(&attachments))
 		array_free(&attachments);
 	test_end();
@@ -406,8 +404,7 @@ static bool test_istream_attachment_extractor_one(const char *body, int err_type
 		memcmp(data, body + attachment_data->used, size) == 0;
 
 cleanup:
-	if (attachment_data != NULL)
-		buffer_free(&attachment_data);
+	buffer_free(&attachment_data);
 	if (array_is_created(&attachments))
 		array_free(&attachments);
 

src/lib-ssl-iostream/ostream-openssl.c

@@ -26,8 +26,7 @@ static void o_stream_ssl_destroy(struct iostream_private *stream)
 
 	sstream->ssl_io->ssl_output = NULL;
 	ssl_iostream_unref(&sstream->ssl_io);
-	if (sstream->buffer != NULL)
-		buffer_free(&sstream->buffer);
+	buffer_free(&sstream->buffer);
 }
 
 static size_t

src/lib-storage/index/imapc/imapc-mail.c

@@ -454,8 +454,7 @@ static void imapc_mail_close(struct mail *_mail)
 			i_error("close(imapc mail) failed: %m");
 		mail->fd = -1;
 	}
-	if (mail->body != NULL)
-		buffer_free(&mail->body);
+	buffer_free(&mail->body);
 	mail->header_fetched = FALSE;
 	mail->body_fetched = FALSE;
 

src/lib-storage/index/imapc/imapc-storage.c

@@ -768,8 +768,7 @@ void imapc_mail_cache_free(struct imapc_mail_cache *cache)
 			i_error("close(imapc cached mail) failed: %m");
 		cache->fd = -1;
 	}
-	if (cache->buf != NULL)
-		buffer_free(&cache->buf);
+	buffer_free(&cache->buf);
 	cache->uid = 0;
 }
 

src/lib-storage/index/index-mail.c

@@ -2047,8 +2047,7 @@ void index_mail_free(struct mail *_mail)
 	i_assert(_mail->transaction->mail_ref_count > 0);
 	_mail->transaction->mail_ref_count--;
 
-	if (mail->header_data != NULL)
-		buffer_free(&mail->header_data);
+	buffer_free(&mail->header_data);
 	if (array_is_created(&mail->header_lines))
 		array_free(&mail->header_lines);
 	if (array_is_created(&mail->header_match))

src/lib-test/test-ostream.c

@@ -19,8 +19,7 @@ static void o_stream_test_destroy(struct iostream_private *stream)
 	struct test_ostream *tstream = (struct test_ostream *)stream;
 
 	timeout_remove(&tstream->to);
-	if (tstream->internal_buf != NULL)
-		buffer_free(&tstream->internal_buf);
+	buffer_free(&tstream->internal_buf);
 }
 
 static int o_stream_test_flush(struct ostream_private *stream)

src/lib/iostream-rawlog.c

@@ -136,8 +136,7 @@ void iostream_rawlog_write(struct rawlog_iostream *rstream,
 void iostream_rawlog_close(struct rawlog_iostream *rstream)
 {
 	o_stream_unref(&rstream->rawlog_output);
-	if (rstream->buffer != NULL)
-		buffer_free(&rstream->buffer);
+	buffer_free(&rstream->buffer);
 }
 
 static void

src/lib/iostream-temp.c

@@ -40,8 +40,7 @@ o_stream_temp_close(struct iostream_private *stream,
 	struct temp_ostream *tstream = (struct temp_ostream *)stream;
 
 	i_close_fd(&tstream->fd);
-	if (tstream->buf != NULL)
-		buffer_free(&tstream->buf);
+	buffer_free(&tstream->buf);
 	i_free(tstream->temp_path_prefix);
 	i_free(tstream->name);
 }

src/lib/istream-seekable.c

@@ -54,8 +54,7 @@ static void i_stream_seekable_destroy(struct iostream_private *stream)
 {
 	struct seekable_istream *sstream = (struct seekable_istream *)stream;
 
-	if (sstream->membuf != NULL)
-		buffer_free(&sstream->membuf);
+	buffer_free(&sstream->membuf);
 	i_stream_unref(&sstream->fd_input);
 	unref_streams(sstream);
 

src/lmtp/client.c

@@ -379,8 +379,7 @@ void client_state_reset(struct client *client, const char *state_name)
 		mailbox_free(&raw_box);
 	}
 
-	if (client->state.mail_data != NULL)
-		buffer_free(&client->state.mail_data);
+	buffer_free(&client->state.mail_data);
 	o_stream_unref(&client->state.mail_data_output);
 	if (client->state.mail_data_fd != -1) {
 		if (close(client->state.mail_data_fd) < 0)

src/plugins/fts/fts-build-mail.c

@@ -578,10 +578,8 @@ fts_build_mail_real(struct fts_backend_update_context *update_ctx,
 	message_decoder_deinit(&decoder);
 	i_free(ctx.content_type);
 	i_free(ctx.content_disposition);
-	if (ctx.word_buf != NULL)
-		buffer_free(&ctx.word_buf);
-	if (ctx.pending_input != NULL)
-		buffer_free(&ctx.pending_input);
+	buffer_free(&ctx.word_buf);
+	buffer_free(&ctx.pending_input);
 	return ret < 0 ? -1 : 1;
 }
 

src/plugins/fts/fts-parser.c

@@ -98,8 +98,7 @@ int fts_parser_deinit(struct fts_parser **_parser)
 
 	*_parser = NULL;
 
-	if (parser->utf8_output != NULL)
-		buffer_free(&parser->utf8_output);
+	buffer_free(&parser->utf8_output);
 	if (parser->v.deinit != NULL)
 		ret = parser->v.deinit(parser);
 	else