Handle longer packets

mysql_common used to ignore `max_allowed_packet`, so we got away with it
(erroneously) being set to a low value. We now set a larger value, and
also do power-of-two growth of the read buffer.

Author: jonhoo

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "msql-srv"
-version = "0.8.6"
+version = "0.8.7"
 edition = "2018"
 
 description = "Bindings for emulating a MySQL/MariaDB server"

src/lib.rs

@@ -281,11 +281,11 @@ impl<B: MysqlShim<W>, R: Read, W: Write> MysqlIntermediary<B, R, W> {
                                 let cols = &[Column {
                                     table: String::new(),
                                     column: "@@max_allowed_packet".to_owned(),
-                                    coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
+                                    coltype: myc::constants::ColumnType::MYSQL_TYPE_LONG,
                                     colflags: myc::constants::ColumnFlags::UNSIGNED_FLAG,
                                 }];
                                 let mut w = w.start(cols)?;
-                                w.write_row(iter::once(1024u16))?;
+                                w.write_row(iter::once(67108864u32))?;
                                 w.finish()?;
                             }
                             _ => {

src/packet.rs

@@ -113,7 +113,7 @@ impl<R: Read> PacketReader<R> {
             self.bytes.drain(0..self.start);
             self.start = 0;
             let end = self.bytes.len();
-            self.bytes.resize(end + 1024, 0);
+            self.bytes.resize(std::cmp::max(4096, end * 2), 0);
             let read = {
                 let mut buf = &mut self.bytes[end..];
                 self.r.read(&mut buf)?

tests/async.rs

@@ -205,6 +205,20 @@ fn no_columns_but_rows() {
     })
 }
 
+#[test]
+fn really_long_query() {
+    let long = "CREATE TABLE `stories` (`id` int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY, `always_null` int, `created_at` datetime, `user_id` int unsigned, `url` varchar(250) DEFAULT '', `title` varchar(150) DEFAULT '' NOT NULL, `description` mediumtext, `short_id` varchar(6) DEFAULT '' NOT NULL, `is_expired` tinyint(1) DEFAULT 0 NOT NULL, `is_moderated` tinyint(1) DEFAULT 0 NOT NULL, `markeddown_description` mediumtext, `story_cache` mediumtext, `merged_story_id` int, `unavailable_at` datetime, `twitter_id` varchar(20), `user_is_author` tinyint(1) DEFAULT 0,  INDEX `index_stories_on_created_at`  (`created_at`), fulltext INDEX `index_stories_on_description`  (`description`),   INDEX `is_idxes`  (`is_expired`, `is_moderated`),  INDEX `index_stories_on_is_expired`  (`is_expired`),  INDEX `index_stories_on_is_moderated`  (`is_moderated`),  INDEX `index_stories_on_merged_story_id`  (`merged_story_id`), UNIQUE INDEX `unique_short_id`  (`short_id`), fulltext INDEX `index_stories_on_story_cache`  (`story_cache`), fulltext INDEX `index_stories_on_title`  (`title`),  INDEX `index_stories_on_twitter_id`  (`twitter_id`),  INDEX `url`  (`url`(191)),  INDEX `index_stories_on_user_id`  (`user_id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;";
+    TestingShim::new(
+        move |q, w| {
+            assert_eq!(q, long);
+            w.start(&[])?.write_col(42).map(|_| ())
+        },
+        |_| unreachable!(),
+        |_, _, _| unreachable!(),
+    )
+    .test(move |db| db.drop_query(long).map(|_| ()))
+}
+
 #[test]
 fn error_response() {
     let err = (ErrorKind::ER_NO, "clearly not");

tests/main.rs

@@ -866,3 +866,20 @@ fn prepared_no_cols() {
         assert_eq!(db.prep_exec("SELECT a, b FROM foo", ()).unwrap().count(), 0);
     })
 }
+
+#[test]
+fn really_long_query() {
+    let long = "CREATE TABLE `stories` (`id` int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY, `always_null` int, `created_at` datetime, `user_id` int unsigned, `url` varchar(250) DEFAULT '', `title` varchar(150) DEFAULT '' NOT NULL, `description` mediumtext, `short_id` varchar(6) DEFAULT '' NOT NULL, `is_expired` tinyint(1) DEFAULT 0 NOT NULL, `is_moderated` tinyint(1) DEFAULT 0 NOT NULL, `markeddown_description` mediumtext, `story_cache` mediumtext, `merged_story_id` int, `unavailable_at` datetime, `twitter_id` varchar(20), `user_is_author` tinyint(1) DEFAULT 0,  INDEX `index_stories_on_created_at`  (`created_at`), fulltext INDEX `index_stories_on_description`  (`description`),   INDEX `is_idxes`  (`is_expired`, `is_moderated`),  INDEX `index_stories_on_is_expired`  (`is_expired`),  INDEX `index_stories_on_is_moderated`  (`is_moderated`),  INDEX `index_stories_on_merged_story_id`  (`merged_story_id`), UNIQUE INDEX `unique_short_id`  (`short_id`), fulltext INDEX `index_stories_on_story_cache`  (`story_cache`), fulltext INDEX `index_stories_on_title`  (`title`),  INDEX `index_stories_on_twitter_id`  (`twitter_id`),  INDEX `url`  (`url`(191)),  INDEX `index_stories_on_user_id`  (`user_id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;";
+    TestingShim::new(
+        move |q, w| {
+            assert_eq!(q, long);
+            w.start(&[])?.finish()
+        },
+        |_| 0,
+        |_, _, _| unreachable!(),
+        |_, _| unreachable!(),
+    )
+    .test(move |db| {
+        db.query(long).unwrap();
+    })
+}