From 9e95551f5c3c8e650759841d69b72eb72f791e4d Mon Sep 17 00:00:00 2001
From: azjezz <azjezz@protonmail.com>
Date: Sat, 7 May 2022 18:53:55 +0100
Subject: [PATCH] feat(shell): introduce stream_unpack function

Signed-off-by: azjezz <azjezz@protonmail.com>
---
 CHANGELOG.md                    |  2 ++
 docs/component/shell.md         |  3 +-
 src/Psl/Internal/Loader.php     |  1 +
 src/Psl/Shell/stream_unpack.php | 56 +++++++++++++++++++++++++++++++++
 src/Psl/Shell/unpack.php        | 27 ++--------------
 5 files changed, 63 insertions(+), 26 deletions(-)
 create mode 100644 src/Psl/Shell/stream_unpack.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0014bd92..711b7387 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -71,3 +71,5 @@
 * **BC** - `$escape_arguments` argument of `Shell\execute` function has been removed.
 * introduced a new `Psl\Shell\ErrorOutputBehavior` enum
 * added a new `$error_output_behavior` argument to `Shell\execute` function, which can be used to return the command error output content, as well as the standard output content.
+* introduced a new `Psl\Shell\unpack` function to unpack packed result of `Shell\execute` ( see `Psl\Shell\ErrorOutputBehavior::Packed` ).
+* introduced a new `Psl\Shell\stream_unpack` function to unpack packed result of `Shell\execute` chunk by chunk, maintaing order ( see `Psl\Shell\ErrorOutputBehavior::Packed` ).
diff --git a/docs/component/shell.md b/docs/component/shell.md
index 7a18a086..52d91a93 100644
--- a/docs/component/shell.md
+++ b/docs/component/shell.md
@@ -13,7 +13,8 @@
 #### `Functions`
 
 - [execute](./../../src/Psl/Shell/execute.php#L41)
-- [unpack](./../../src/Psl/Shell/unpack.php#L20)
+- [stream_unpack](./../../src/Psl/Shell/stream_unpack.php#L30)
+- [unpack](./../../src/Psl/Shell/unpack.php#L16)
 
 #### `Enums`
 
diff --git a/src/Psl/Internal/Loader.php b/src/Psl/Internal/Loader.php
index e0af18b8..e31e992d 100644
--- a/src/Psl/Internal/Loader.php
+++ b/src/Psl/Internal/Loader.php
@@ -379,6 +379,7 @@ final class Loader
         'Psl\Encoding\Hex\decode',
         'Psl\Shell\execute',
         'Psl\Shell\unpack',
+        'Psl\Shell\stream_unpack',
         'Psl\Shell\Internal\escape_argument',
         'Psl\Html\encode',
         'Psl\Html\encode_special_characters',
diff --git a/src/Psl/Shell/stream_unpack.php b/src/Psl/Shell/stream_unpack.php
new file mode 100644
index 00000000..6701ffcb
--- /dev/null
+++ b/src/Psl/Shell/stream_unpack.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Shell;
+
+use Generator;
+use Psl\Str;
+
+use function unpack as byte_unpack;
+
+/**
+ * Stream unpack the result of `Shell\execute()` when using `ErrorOutputBehavior::Packed` error output behavior,
+ * maintaining the outputting order, chunk by chunk.
+ *
+ * @param string $content
+ *
+ * @throws Exception\InvalidArgumentException If $content is invalid.
+ *
+ * @return Generator<1|2, string, void, void> Generator where the key is either 1 ( representing the standard output ),
+ *                                            or 2 ( representing the standard error output ), and the value is the output chunk.
+ *
+ * Example:
+ *
+ *      Shell\stream_unpack(
+ *          Shell\execute('php', ['-r', 'fwrite(STDOUT, "a"); fwrite(STDERR, "b"); fwrite(STDOUT, "c");'], null, [], ErrorOutputBehavior::Packed),
+ *      );
+ *      => Generator(1 => "a", 2 => "b", 1 => "c")
+ */
+function stream_unpack(string $content): Generator
+{
+    while ($content !== '') {
+        if (Str\Byte\length($content) < 5) {
+            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
+        }
+
+        $headers = byte_unpack('C1type/N1size', Str\Byte\slice($content, 0, 5));
+        /** @var int<0, max> $type */
+        $type = (int) $headers['type'];
+        /** @var int<0, max> $size */
+        $size = (int) $headers['size'];
+
+        if ($size > (Str\Byte\length($content) - 5)) {
+            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
+        }
+
+        $chunk = Str\Byte\slice($content, 5, $size);
+        $content = Str\Byte\slice($content, $size + 5);
+
+        if ($type === 1 || $type === 2) {
+            yield $type => $chunk;
+        } else {
+            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
+        }
+    }
+}
diff --git a/src/Psl/Shell/unpack.php b/src/Psl/Shell/unpack.php
index a304c9f9..e2f7928c 100644
--- a/src/Psl/Shell/unpack.php
+++ b/src/Psl/Shell/unpack.php
@@ -4,10 +4,6 @@
 
 namespace Psl\Shell;
 
-use Psl\Str;
-
-use function unpack as byte_unpack;
-
 /**
  * Unpack the result of `Shell\execute()` when using `ErrorOutputBehavior::Packed` error output behavior.
  *
@@ -20,30 +16,11 @@
 function unpack(string $content): array
 {
     $result = ['', ''];
-    while ($content !== '') {
-        if (Str\Byte\length($content) < 5) {
-            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
-        }
-
-        $headers = byte_unpack('C1type/N1size', Str\Byte\slice($content, 0, 5));
-        /** @var int<0, max> $type */
-        $type = (int) $headers['type'];
-        /** @var int<0, max> $size */
-        $size = (int) $headers['size'];
-
-        if ($size > (Str\Byte\length($content) - 5)) {
-            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
-        }
-
-        $chunk = Str\Byte\slice($content, 5, $size);
-        $content = Str\Byte\slice($content, $size + 5);
-
+    foreach (stream_unpack($content) as $type => $chunk) {
         if ($type === 1) {
             $result[0] .= $chunk;
-        } elseif ($type === 2) {
-            $result[1] .= $chunk;
         } else {
-            throw new Exception\InvalidArgumentException('$content contains an invalid header value.');
+            $result[1] .= $chunk;
         }
     }