fix loading multiple chunks in memory

Author: Baptouuuu

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- `Innmind\Filesystem\File\Content::ofChunks()->size()` no longer load more than one chunk size in memory
+
 ## 7.5.0 - 2024-03-16
 
 ### Changed

fixtures/sample.pdf

@@ -1,5 +1,6 @@
 <?php
 declare(strict_types = 1);
+declare(ticks = 1);
 
 use Innmind\Filesystem\File\{
     Content as Model,
@@ -238,4 +239,27 @@ static function($assert, $a, $b) use ($io, $capabilities) {
             $assert->throws(static fn() => $b($content));
         },
     );
+
+    yield test(
+        'Content::ofChunks()->size() does not load the whole file in memory',
+        static function($assert) use ($io, $capabilities) {
+            $atPath = Model::atPath(
+                $capabilities->readable(),
+                $io,
+                Path::of('fixtures/sample.pdf'),
+            );
+            $content = Model::ofChunks($atPath->chunks());
+
+            $assert
+                ->memory(static function() use ($assert, $content) {
+                    $size = $content->size()->match(
+                        static fn($size) => $size->toInt(),
+                        static fn() => null,
+                    );
+                    $assert->same(5951532, $size);
+                })
+                ->inLessThan()
+                ->kilobytes(600);
+        },
+    );
 };

proofs/file/content.php

@@ -3,6 +3,7 @@
 
 namespace Innmind\Filesystem\File\Content;
 
+use Innmind\Stream\Stream\Size;
 use Innmind\Immutable\{
     Sequence,
     SideEffect,
@@ -81,7 +82,16 @@ public function reduce($carry, callable $reducer)
 
     public function size(): Maybe
     {
-        return $this->content()->size();
+        return Maybe::just(
+            $this
+                ->chunks
+                ->map(static fn($chunk) => $chunk->toEncoding(Str\Encoding::ascii))
+                ->map(static fn($chunk) => $chunk->length())
+                ->reduce(
+                    0,
+                    static fn(int $total, int $chunk) => $total + $chunk,
+                ),
+        )->map(static fn($size) => new Size($size));
     }
 
     public function toString(): string