Munge PostgreSQL queries instead of adding explicit casts

PDO does not adequately inform PostgreSQL of a parameter's type, so type
casts are required. Rather than adding these to each query manually, the
queries are instead processed to add type hints automatically.

Unfortunately the queries are processed rather naively; question-mark
characters in string constants, identifiers, regex patterns, or geometry
operators will break things spectacularly.

lib/Database.php

@@ -385,7 +385,7 @@ class Database {
         // SQL will happily accept duplicates (null is not unique), so we must do this check ourselves
         $p = $this->db->prepare(
             "WITH RECURSIVE
-                target as (select ? as userid, cast(? as bigint) as source, cast(? as bigint) as dest, ? as rename),
+                target as (select ? as userid, ? as source, ? as dest, ? as rename),
                 folders as (SELECT id from arsse_folders join target on owner = userid and coalesce(parent,0) = source union select arsse_folders.id as id from arsse_folders join folders on arsse_folders.parent=folders.id)
             ".
             "SELECT
@@ -480,7 +480,7 @@ class Database {
                 join arsse_feeds on feed = arsse_feeds.id
                 left join topmost on folder=f_id"
         );
-        $q->setOrder("pinned desc, title collate nocase");
+        $q->setOrder("pinned desc, coalesce(arsse_subscriptions.title, arsse_feeds.title) collate nocase");
         // define common table expressions
         $q->setCTE("userdata(userid)", "SELECT ?", "str", $user);  // the subject user; this way we only have to pass it to prepare() once
         // topmost folders belonging to the user

lib/Db/PDODriver.php

@@ -28,9 +28,9 @@ trait PDODriver {
         }
         $changes = $r->rowCount();
         try {
-            $lastId = 0;
-            $lastId = $this->db->lastInsertId();
+            $lastId = ($changes) ? $this->db->lastInsertId() : 0;
         } catch (\PDOException $e) { // @codeCoverageIgnore
+            $lastId = 0;
         }
         return new PDOResult($r, [$changes, $lastId]);
     }

lib/Db/PDOError.php

@@ -7,14 +7,15 @@ declare(strict_types=1);
 namespace JKingWeb\Arsse\Db;
 
 trait PDOError {
-    public function exceptionBuild(): array {
-        if ($this instanceof Statement) {
+    public function exceptionBuild(bool $statementError = null): array {
+        if ($statementError ?? ($this instanceof Statement)) {
             $err = $this->st->errorInfo();
         } else {
             $err = $this->db->errorInfo();
         }
         switch ($err[0]) {
             case "22P02":
+            case "42804":
                 return [ExceptionInput::class, 'engineTypeViolation', $err[2]];
             case "23000":
             case "23502":

lib/Db/PDOStatement.php

@@ -28,10 +28,10 @@ class PDOStatement extends AbstractStatement {
     }
 
     public function __destruct() {
-        unset($this->st);
+        unset($this->st, $this->db);
     }
 
-    public function runArray(array $values = []): \JKingWeb\Arsse\Db\Result {
+    public function runArray(array $values = []): Result {
         $this->st->closeCursor();
         $this->bindValues($values);
         try {
@@ -42,9 +42,9 @@ class PDOStatement extends AbstractStatement {
         }
         $changes = $this->st->rowCount();
         try {
-            $lastId = 0;
-            $lastId = $this->db->lastInsertId();
+            $lastId = ($changes) ? $this->db->lastInsertId() : 0;
         } catch (\PDOException $e) { // @codeCoverageIgnore
+            $lastId = 0;
         }
         return new PDOResult($this->st, [$changes, $lastId]);
     }

lib/Db/PostgreSQL/PDODriver.php

@@ -44,4 +44,8 @@ class PDODriver extends Driver {
     public static function driverName(): string {
         return Arsse::$lang->msg("Driver.Db.PostgreSQLPDO.Name");
     }
+
+    public function prepareArray(string $query, array $paramTypes): \JKingWeb\Arsse\Db\Statement {
+        return new PDOStatement($this->db, $query, $paramTypes);
+    }
 }

lib/Db/PostgreSQL/PDOStatement.php

@@ -0,0 +1,77 @@
+<?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\PostgreSQL;
+
+class PDOStatement extends \JKingWeb\Arsse\Db\AbstractStatement {
+    use \JKingWeb\Arsse\Db\PDOError;
+
+    const BINDINGS = [
+        "integer"   => "bigint",
+        "float"     => "decimal",
+        "datetime"  => "timestamp",
+        "binary"    => "bytea",
+        "string"    => "text",
+        "boolean"   => "smallint", // FIXME: using boolean leads to incompatibilities with versions of SQLite bundled prior to PHP 7.3
+    ];
+
+    protected $db;
+    protected $st;
+    protected $qOriginal;
+    protected $qMunged;
+    protected $bindings;
+
+    public function __construct(\PDO $db, string $query, array $bindings = []) {
+        $this->db = $db; // both db and st are the same object due to the logic of the PDOError handler
+        $this->qOriginal = $query;
+        $this->retypeArray($bindings);
+    }
+
+    public function __destruct() {
+        unset($this->db, $this->st);
+    }
+
+    public function retypeArray(array $bindings, bool $append = false): bool {
+        if ($append) {
+            return parent::retypeArray($bindings, $append);
+        } else {
+            $this->bindings = $bindings;
+            parent::retypeArray($bindings, $append);
+            $this->qMunged = self::mungeQuery($this->qOriginal, $this->types, false);
+            try {
+                $s = $this->db->prepare($this->qMunged);
+                $this->st = new \JKingWeb\Arsse\Db\PDOStatement($this->db, $s, $this->bindings);
+            } catch (\PDOException $e) {
+                list($excClass, $excMsg, $excData) = $this->exceptionBuild(true);
+                throw new $excClass($excMsg, $excData);
+            }
+        }
+        return true;
+    }
+
+    public static function mungeQuery(string $q, array $types, bool $mungeParamMarkers = true): string {
+        $q = explode("?", $q);
+        $out = "";
+        for ($b = 1; $b < sizeof($q); $b++) {
+            $a = $b - 1;
+            $mark = $mungeParamMarkers ? "\$$b" : "?";
+            $type = isset($types[$a]) ? "::".self::BINDINGS[$types[$a]] : "";
+            $out .= $q[$a].$mark.$type;
+        }
+        $out .= array_pop($q);
+        return $out;
+    }
+
+    public function runArray(array $values = []): \JKingWeb\Arsse\Db\Result {
+        return $this->st->runArray($values);
+    }
+
+    /** @codeCoverageIgnore */
+    protected function bindValue($value, string $type, int $position): bool {
+        // stub required by abstract parent, but never used
+        return $value;
+    }
+}

tests/cases/Db/BaseStatement.php

@@ -59,7 +59,7 @@ abstract class BaseStatement extends \JKingWeb\Arsse\Test\AbstractTest {
     /** @dataProvider provideBindings */
     public function testBindATypedValue($value, string $type, string $exp) {
         if ($exp=="null") {
-            $query = "SELECT (cast(? as text) is null) as pass";
+            $query = "SELECT (? is null) as pass";
         } else {
             $query = "SELECT ($exp = ?) as pass";
         }
@@ -76,7 +76,7 @@ abstract class BaseStatement extends \JKingWeb\Arsse\Test\AbstractTest {
             $this->markTestSkipped("Correct handling of binary data with PostgreSQL is currently unknown");
         }
         if ($exp=="null") {
-            $query = "SELECT (cast(? as text) is null) as pass";
+            $query = "SELECT (? is null) as pass";
         } else {
             $query = "SELECT ($exp = ?) as pass";
         }

tests/cases/Db/PostgreSQL/TestStatement.php

@@ -13,7 +13,7 @@ class TestStatement extends \JKingWeb\Arsse\TestCase\Db\BaseStatement {
     protected static $implementation = "PDO PostgreSQL";
 
     protected function makeStatement(string $q, array $types = []): array {
-        return [static::$interface, static::$interface->prepare($q), $types];
+        return [static::$interface, $q, $types];
     }
 
     protected function decorateTypeSyntax(string $value, string $type): string {

tests/lib/DatabaseInformation.php

@@ -161,10 +161,10 @@ class DatabaseInformation {
             'PDO PostgreSQL' => [
                 'pdo' => true,
                 'backend' => "PostgreSQL",
-                'statementClass' => \JKingWeb\Arsse\Db\PDOStatement::class,
+                'statementClass' => \JKingWeb\Arsse\Db\PostgreSQL\PDOStatement::class,
                 'resultClass' => \JKingWeb\Arsse\Db\PDOResult::class,
                 'driverClass' => \JKingWeb\Arsse\Db\PostgreSQL\PDODriver::class,
-                'stringOutput' => true,
+                'stringOutput' => false,
                 'interfaceConstructor' => function() {
                     $connString = \JKingWeb\Arsse\Db\PostgreSQL\Driver::makeConnectionString(true, Arsse::$conf->dbPostgreSQLUser, Arsse::$conf->dbPostgreSQLPass, Arsse::$conf->dbPostgreSQLDb, Arsse::$conf->dbPostgreSQLHost, Arsse::$conf->dbPostgreSQLPort, "");
                     try {