Work around various SQLite-related problems

- WAL mode was not getting set properly
- Queries using the PDO driver could fail because PDO sucks

lib/AbstractException.php

@@ -45,6 +45,7 @@ abstract class AbstractException extends \Exception {
         "Db/Exception.savepointInvalid"               => 10226,
         "Db/Exception.savepointStale"                 => 10227,
         "Db/Exception.resultReused"                   => 10228,
+        "Db/ExceptionRetry.schemaChange"              => 10229,
         "Db/ExceptionInput.missing"                   => 10231,
         "Db/ExceptionInput.whitespace"                => 10232,
         "Db/ExceptionInput.tooLong"                   => 10233,

lib/Db/ExceptionRetry.php

@@ -0,0 +1,10 @@
+<?php
+/** @license MIT
+ * Copyright 2017 J. King, Dustin Wilson et al.
+ * See LICENSE and AUTHORS files for details */
+
+declare(strict_types=1);
+namespace JKingWeb\Arsse\Db;
+
+class ExceptionRetry extends \JKingWeb\Arsse\AbstractException {
+}

lib/Db/SQLite3/AbstractPDODriver.php

@@ -0,0 +1,11 @@
+<?php
+/** @license MIT
+ * Copyright 2017 J. King, Dustin Wilson et al.
+ * See LICENSE and AUTHORS files for details */
+
+declare(strict_types=1);
+namespace JKingWeb\Arsse\Db\SQLite3;
+
+abstract class AbstractPDODriver extends Driver {
+    use \JKingWeb\Arsse\Db\PDODriver;
+}

lib/Db/SQLite3/Driver.php

@@ -17,6 +17,7 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
     const TRANSACTIONAL_LOCKS = true;
 
     const SQLITE_BUSY = 5;
+    const SQLITE_SCHEMA = 17;
     const SQLITE_CONSTRAINT = 19;
     const SQLITE_MISMATCH = 20;
 
@@ -122,6 +123,10 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
     }
 
     public function schemaUpdate(int $to, string $basePath = null): bool {
+        if ($to == 1) {
+            // if we're initializing the database for the first time, switch to WAL mode
+            $this->exec("PRAGMA journal_mode = wal");
+        }
         // turn off foreign keys
         $this->exec("PRAGMA foreign_keys = no");
         // run the generic updater

lib/Db/SQLite3/ExceptionBuilder.php

@@ -7,6 +7,7 @@ declare(strict_types=1);
 namespace JKingWeb\Arsse\Db\SQLite3;
 
 use JKingWeb\Arsse\Db\Exception;
+use JKingWeb\Arsse\Db\ExceptionRetry;
 use JKingWeb\Arsse\Db\ExceptionInput;
 use JKingWeb\Arsse\Db\ExceptionTimeout;
 
@@ -19,6 +20,8 @@ trait ExceptionBuilder {
         switch ($code) {
             case Driver::SQLITE_BUSY:
                 return [ExceptionTimeout::class, 'general', $msg];
+            case Driver::SQLITE_SCHEMA:
+                return [ExceptionRetry::class, 'schemaChange', $msg];
             case Driver::SQLITE_CONSTRAINT:
                 return [ExceptionInput::class, 'engineConstraintViolation', $msg];
             case Driver::SQLITE_MISMATCH:

lib/Db/SQLite3/PDODriver.php

@@ -11,9 +11,7 @@ use JKingWeb\Arsse\Db\Exception;
 use JKingWeb\Arsse\Db\ExceptionInput;
 use JKingWeb\Arsse\Db\ExceptionTimeout;
 
-class PDODriver extends Driver {
-    use \JKingWeb\Arsse\Db\PDODriver;
-
+class PDODriver extends AbstractPDODriver {
     protected $db;
 
     public static function requirementsMet(): bool {
@@ -49,4 +47,40 @@ class PDODriver extends Driver {
     public function prepareArray(string $query, array $paramTypes): \JKingWeb\Arsse\Db\Statement {
         return new PDOStatement($this->db, $query, $paramTypes);
     }
+
+    /** @codeCoverageIgnore */
+    public function exec(string $query): bool {
+        // because PDO uses sqlite3_prepare() internally instead of sqlite3_prepare_v2(), 
+        // we have to retry ourselves in cases of schema changes
+        // the SQLite3 class is not similarly affected
+        $attempts = 0;
+        retry:
+        try {
+            return parent::exec($query);
+        } catch (\JKingWeb\Arsse\Db\ExceptionRetry $e) {
+            if (++$attempts > 50) {
+                throw $e;
+            } else {
+                goto retry;
+            }
+        }
+    }
+
+    /** @codeCoverageIgnore */
+    public function query(string $query): \JKingWeb\Arsse\Db\Result {
+        // because PDO uses sqlite3_prepare() internally instead of sqlite3_prepare_v2(), 
+        // we have to retry ourselves in cases of schema changes
+        // the SQLite3 class is not similarly affected
+        $attempts = 0;
+        retry:
+        try {
+            return parent::query($query);
+        } catch (\JKingWeb\Arsse\Db\ExceptionRetry $e) {
+            if (++$attempts > 50) {
+                throw $e;
+            } else {
+                goto retry;
+            }
+        }
+    }
 }

lib/Db/SQLite3/PDOStatement.php

@@ -9,4 +9,23 @@ namespace JKingWeb\Arsse\Db\SQLite3;
 class PDOStatement extends \JKingWeb\Arsse\Db\PDOStatement {
     use ExceptionBuilder;
     use \JKingWeb\Arsse\Db\PDOError;
+
+    /** @codeCoverageIgnore */
+    public function runArray(array $values = []): \JKingWeb\Arsse\Db\Result {
+        // because PDO uses sqlite3_prepare() internally instead of sqlite3_prepare_v2(), 
+        // we have to retry ourselves in cases of schema changes
+        // the SQLite3 class is not similarly affected
+        $attempts = 0;
+        retry:
+        try {
+            return parent::runArray($values);
+        } catch (\JKingWeb\Arsse\Db\ExceptionRetry $e) {
+            if (++$attempts > 50) {
+                throw $e;
+            } else {
+                $this->st = $this->db->prepare($this->st->queryString);
+                goto retry;
+            }
+        }
+    }
 }

locale/en.php

@@ -120,6 +120,7 @@ return [
     'Exception.JKingWeb/Arsse/Db/Exception.savepointStale'                 => 'Tried to {action} stale savepoint {index}',
     // indicates programming error
     'Exception.JKingWeb/Arsse/Db/Exception.resultReused'                   => 'Result set already iterated',
+    'Exception.JKingWeb/Arsse/Db/ExceptionRetry.schemaChange'              => '{0}',
     'Exception.JKingWeb/Arsse/Db/ExceptionInput.missing'                   => 'Required field "{field}" missing while performing action "{action}"',
     'Exception.JKingWeb/Arsse/Db/ExceptionInput.whitespace'                => 'Field "{field}" of action "{action}" may not contain only whitespace',
     'Exception.JKingWeb/Arsse/Db/ExceptionInput.tooLong'                   => 'Field "{field}" of action "{action}" has a maximum length of {max}',

sql/SQLite3/0.sql

@@ -2,9 +2,6 @@
 -- Copyright 2017 J. King, Dustin Wilson et al.
 -- See LICENSE and AUTHORS files for details
 
--- Make the database WAL-journalled; this is persitent
-PRAGMA journal_mode = wal;
-
 create table arsse_meta(
 -- application metadata
     key text primary key not null,                                                                          -- metadata key

tests/cases/DatabaseDrivers/SQLite3.php

@@ -28,7 +28,7 @@ trait SQLite3 {
     }
     
     public static function dbTableList($db): array {
-        $listTables = "SELECT name from sqlite_master where type = 'table' and name like 'arsse_%'";
+        $listTables = "SELECT name from sqlite_master where type = 'table' and name like 'arsse^_%' escape '^'";
         if ($db instanceof Driver) {
             $tables = $db->query($listTables)->getAll();
             $tables = sizeof($tables) ? array_column($tables, "name") : [];