WIP

examples/basic.php

@@ -14,8 +14,7 @@ Amp\Loop::run(function () {
     /** @var \Amp\Postgres\ResultSet $result */
     $result = yield $connection->query('SHOW ALL');
 
-    while (yield $result->advance()) {
+    while ($row = yield $result->continue()) {
-        $row = $result->getCurrent();
         \printf("%-35s = %s (%s)\n", $row['name'], $row['setting'], $row['description']);
     }
 });

examples/listen.php

@@ -31,8 +31,7 @@ Loop::run(function () {
         return $pool->notify($channel, "Data 2"); // Send second notification.
     });
 
-    while (yield $listener->advance()) {
+    while ($notification = yield $listener->continue()) {
-        $notification = $listener->getCurrent();
         \printf(
             "Received notification from PID %d on channel '%s' with payload: %s\n",
             $notification->pid,

examples/multi-listen.php

@@ -3,9 +3,9 @@
 
 require \dirname(__DIR__) . '/vendor/autoload.php';
 
-use Amp\Iterator;
 use Amp\Loop;
 use Amp\Postgres;
+use Amp\Stream;
 
 Loop::run(function () {
     $config = Postgres\ConnectionConfig::fromString('host=localhost user=postgres');
@@ -51,10 +51,9 @@ Loop::run(function () {
         return $pool->notify($channel1, "Data 1.2");
     });
 
-    $iterator = Iterator\merge([$listener1, $listener2]); // Merge both listeners into single iterator.
+    $stream = Stream\merge([$listener1, $listener2]); // Merge both listeners into single iterator.
 
-    while (yield $iterator->advance()) {
+    while ($notification = yield $stream->continue()) {
-        $notification = $iterator->getCurrent();
         \printf(
             "Received notification from PID %d on channel '%s' with payload: %s\n",
             $notification->pid,

examples/transaction.php

@@ -29,8 +29,7 @@ Amp\Loop::run(function () {
 
     $format = "%-20s | %-10s\n";
     \printf($format, 'TLD', 'Domain');
-    while (yield $result->advance()) {
+    while ($row = yield $result->continue()) {
-        $row = $result->getCurrent();
         \printf($format, $row['domain'], $row['tld']);
     }
 

src/PgSqlResultSet.php

@@ -25,12 +25,17 @@ final class PgSqlResultSet implements ResultSet
     /** @var Internal\ArrayParser */
     private $parser;
 
+    /** @var Promise<ResultSet|null> */
+    private $nextResult;
+
     /**
      * @param resource $handle PostgreSQL result resource.
+     * @param Promise<ResultSet|null> $nextResult
      */
-    public function __construct($handle)
+    public function __construct($handle, Promise $nextResult)
     {
         $this->handle = $handle;
+        $this->nextResult = $nextResult;
 
         $numFields = \pg_num_fields($this->handle);
         for ($i = 0; $i < $numFields; ++$i) {
@@ -73,14 +78,14 @@ final class PgSqlResultSet implements ResultSet
         return new Success($this->processRow($result));
     }
 
-    public function dispose()
+    public function dispose(): void
     {
         $this->handle = null;
     }
 
     public function getNextResultSet(): Promise
     {
-        return new Success;
+        return $this->nextResult;
     }
 
     /**

src/PqBufferedResultSet.php

@@ -16,13 +16,18 @@ final class PqBufferedResultSet implements ResultSet
     /** @var int */
     private $position = 0;
 
+    /** @var Promise<ResultSet|null> */
+    private $nextResult;
+
     /**
      * @param pq\Result $result PostgreSQL result object.
+     * @param Promise<ResultSet|null> $nextResult Promise for next result set.
      */
-    public function __construct(pq\Result $result)
+    public function __construct(pq\Result $result, Promise $nextResult)
     {
         $this->result = $result;
         $this->result->autoConvert = pq\Result::CONV_SCALAR | pq\Result::CONV_ARRAY;
+        $this->nextResult = $nextResult;
     }
 
     /**
@@ -44,14 +49,14 @@ final class PqBufferedResultSet implements ResultSet
     /**
      * @inheritDoc
      */
-    public function dispose()
+    public function dispose(): void
     {
         $this->result = null;
     }
 
     public function getNextResultSet(): Promise
     {
-        return new Success; // Empty stub for now.
+        return $this->nextResult;
     }
 
     public function getFieldCount(): int

src/PqHandle.php

@@ -169,8 +169,6 @@ final class PqHandle implements Handle
      *
      * @return \Generator
      *
-     * @resolve \Amp\Sql\CommandResult|\pq\Statement
-     *
      * @throws FailureException
      */
     private function send(?string $sql, callable $method, ...$args): \Generator
@@ -208,19 +206,64 @@ final class PqHandle implements Handle
             throw new FailureException("Unknown query result");
         }
 
+        $result = $this->makeResult($result, $sql);
+
+        if ($handle instanceof pq\Statement) {
+            return $handle; // Will be wrapped into a PqStatement object.
+        }
+
+        return $result;
+
+//        switch ($result->status) {
+//            case pq\Result::EMPTY_QUERY:
+//                throw new QueryError("Empty query string");
+//
+//            case pq\Result::COMMAND_OK:
+//                if ($handle instanceof pq\Statement) {
+//                    return $handle; // Will be wrapped into a PqStatement object.
+//                }
+//
+//                return new PqCommandResult($result);
+//
+//            case pq\Result::TUPLES_OK:
+//                return new PqBufferedResultSet($result);
+//
+//            case pq\Result::SINGLE_TUPLE:
+//                $this->busy = new Deferred;
+//                $result = new PqUnbufferedResultSet(
+//                    coroutine(\Closure::fromCallable([$this, 'fetch'])),
+//                    $result,
+//                    \Closure::fromCallable([$this, 'release'])
+//                );
+//                return $result;
+//
+//            case pq\Result::NONFATAL_ERROR:
+//            case pq\Result::FATAL_ERROR:
+//                throw new QueryExecutionError($result->errorMessage, $result->diag, null, $sql ?? '');
+//
+//            case pq\Result::BAD_RESPONSE:
+//                throw new FailureException($result->errorMessage);
+//
+//            default:
+//                throw new FailureException("Unknown result status");
+//        }
+    }
+
+    private function makeResult(pq\Result $result, ?string $sql)
+    {
         switch ($result->status) {
             case pq\Result::EMPTY_QUERY:
                 throw new QueryError("Empty query string");
 
             case pq\Result::COMMAND_OK:
-                if ($handle instanceof pq\Statement) {
-                    return $handle; // Will be wrapped into a PqStatement object.
-                }
-
                 return new PqCommandResult($result);
 
             case pq\Result::TUPLES_OK:
-                return new PqBufferedResultSet($result);
+                if (!$this->handle->busy && ($next = $this->handle->getResult()) instanceof pq\Result) {
+                    $next = new Success($this->makeResult($next, $sql));
+                }
+
+                return new PqBufferedResultSet($result, $next ?? new Success);
 
             case pq\Result::SINGLE_TUPLE:
                 $this->busy = new Deferred;
@@ -268,6 +311,14 @@ final class PqHandle implements Handle
 
         switch ($result->status) {
             case pq\Result::TUPLES_OK: // End of result set.
+                while (!$this->handle->busy && ($next = $this->handle->getResult()) instanceof pq\Result) {
+                    if ($next->status === pq\Result::TUPLES_OK) {
+                        continue;
+                    }
+
+                    return $this->makeResult($result, null);
+                }
+
                 return null;
 
             case pq\Result::SINGLE_TUPLE:

src/PqUnbufferedResultSet.php

@@ -3,9 +3,9 @@
 namespace Amp\Postgres;
 
 use Amp\AsyncGenerator;
+use Amp\Deferred;
 use Amp\DisposedException;
 use Amp\Promise;
-use Amp\Success;
 use pq;
 
 final class PqUnbufferedResultSet implements ResultSet
@@ -16,8 +16,11 @@ final class PqUnbufferedResultSet implements ResultSet
     /** @var AsyncGenerator */
     private $generator;
 
+    /** @var Deferred */
+    private $next;
+
     /**
-     * @param callable():Promise<pq\Result> $fetch Function to fetch next result row.
+     * @param callable():Promise<pq\Result|ResultSet|null> $fetch Function to fetch next result row.
      * @param \pq\Result $result PostgreSQL result object.
      * @param callable():void $release Invoked once the result has been fully consumed.
      */
@@ -25,8 +28,9 @@ final class PqUnbufferedResultSet implements ResultSet
     {
         $this->numCols = $result->numCols;
 
+        $this->next = $deferred = new Deferred;
         $this->generator = new AsyncGenerator(static function (callable $yield) use (
-            $release, $result, $fetch
+            $deferred, $release, $result, $fetch
         ): \Generator {
             try {
                 do {
@@ -37,18 +41,26 @@ final class PqUnbufferedResultSet implements ResultSet
                 } while ($result instanceof pq\Result);
             } catch (DisposedException $exception) {
                 // Discard remaining rows in the result set.
-                while ((yield $promise) instanceof pq\Result) {
+                while (($result = yield $promise) instanceof pq\Result) {
                     $promise = $fetch();
                 }
             } finally {
+                if ($result instanceof ResultSet) {
+                    $deferred->resolve($result);
+                    return;
+                }
+
+                // Only release if there was no next result set.
                 $release();
+
+                $deferred->resolve(null);
             }
         });
     }
 
     public function getNextResultSet(): Promise
     {
-        return new Success; // Empty stub for now.
+        return $this->next->promise();
     }
 
     /**
@@ -62,7 +74,7 @@ final class PqUnbufferedResultSet implements ResultSet
     /**
      * @inheritDoc
      */
-    public function dispose()
+    public function dispose(): void
     {
         $this->generator->dispose();
     }

test/AbstractLinkTest.php

@@ -73,8 +73,6 @@ abstract class AbstractLinkTest extends AsyncTestCase
 
     public function testMultipleQueryWithTupleResult(): \Generator
     {
-        $this->markTestSkipped('Unimplemented');
-
         /** @var \Amp\Postgres\ResultSet $result */
         $result = yield $this->connection->query("SELECT * FROM test; SELECT * FROM test");