Add path mapper

src/Psalm/Internal/LanguageServer/PathMapper.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace Psalm\Internal\LanguageServer;
+
+/** @internal */
+final class PathMapper
+{
+    private string $serverRoot;
+    private ?string $clientRoot;
+
+    public function __construct(string $serverRoot, ?string $clientRoot = null)
+    {
+        $this->serverRoot = $this->sanitizeFolderPath($serverRoot);
+        $this->clientRoot = $this->sanitizeFolderPath($clientRoot);
+    }
+
+    public function configureClientRoot(string $clientRoot): void
+    {
+        // ignore if preconfigured
+        if ($this->clientRoot === null) {
+            $this->clientRoot = $this->sanitizeFolderPath($clientRoot);
+        }
+    }
+
+    public function mapClientToServer(string $clientPath): string
+    {
+        if ($this->clientRoot === null) {
+            return $clientPath;
+        }
+
+        if (substr($clientPath, 0, strlen($this->clientRoot)) === $this->clientRoot) {
+            return $this->serverRoot . substr($clientPath, strlen($this->clientRoot));
+        }
+
+        return $clientPath;
+    }
+
+    public function mapServerToClient(string $serverPath): string
+    {
+        if ($this->clientRoot === null) {
+            return $serverPath;
+        }
+        if (substr($serverPath, 0, strlen($this->serverRoot)) === $this->serverRoot) {
+            return $this->clientRoot . substr($serverPath, strlen($this->serverRoot));
+        }
+        return $serverPath;
+    }
+
+    /** @return ($path is null ? null : string) */
+    private function sanitizeFolderPath(?string $path): ?string
+    {
+        if ($path === null) {
+            return $path;
+        }
+        return rtrim($path, '/');
+    }
+}

tests/LanguageServer/PathMapperTest.php

@@ -0,0 +1,75 @@
+<?php
+
+namespace Psalm\Tests\LanguageServer;
+
+use PHPUnit\Framework\TestCase;
+use Psalm\Internal\LanguageServer\PathMapper;
+
+final class PathMapperTest extends TestCase
+{
+    public function testUsesUpdatedClientRoot(): void
+    {
+        $mapper = new PathMapper('/var/www');
+        $mapper->configureClientRoot('/home/user/src/project');
+        $this->assertSame(
+            '/home/user/src/project/filename.php',
+            $mapper->mapServerToClient('/var/www/filename.php')
+        );
+    }
+
+    public function testIgnoresClientRootIfItWasPreconfigures(): void
+    {
+        $mapper = new PathMapper('/var/www', '/home/user/src/project');
+        // this will be ignored
+        $mapper->configureClientRoot('/home/anotheruser/Projects/project');
+
+        $this->assertSame(
+            '/home/user/src/project/filename.php',
+            $mapper->mapServerToClient('/var/www/filename.php')
+        );
+    }
+
+    /**
+     * @dataProvider mappingProvider
+     */
+    public function testMapsClientToServer(
+        string $serverRoot,
+        ?string $clientRootPreconfigured,
+        string $clientRootProvidedLater,
+        string $clientPath,
+        string $serverPath
+    ): void {
+        $mapper = new PathMapper($serverRoot, $clientRootPreconfigured);
+        $mapper->configureClientRoot($clientRootProvidedLater);
+        $this->assertSame(
+            $serverPath,
+            $mapper->mapClientToServer($clientPath)
+        );
+    }
+
+    /** @dataProvider mappingProvider */
+    public function testMapsServerToClient(
+        string $serverRoot,
+        ?string $clientRootPreconfigured,
+        string $clientRootProvidedLater,
+        string $clientPath,
+        string $serverPath
+    ): void {
+        $mapper = new PathMapper($serverRoot, $clientRootPreconfigured);
+        $mapper->configureClientRoot($clientRootProvidedLater);
+        $this->assertSame(
+            $clientPath,
+            $mapper->mapServerToClient($serverPath)
+        );
+    }
+
+    /** @return iterable<int, array{string, string|null, string, string, string}> */
+    public static function mappingProvider(): iterable
+    {
+        yield ["/var/a",  null,             "/user/project", "/user/project/filename.php", "/var/a/filename.php"];
+        yield ["/var/a",  "/user/project",  "/whatever",     "/user/project/filename.php", "/var/a/filename.php"];
+        yield ["/var/a/", "/user/project",  "/whatever",     "/user/project/filename.php", "/var/a/filename.php"];
+        yield ["/var/a",  "/user/project/", "/whatever",     "/user/project/filename.php", "/var/a/filename.php"];
+        yield ["/var/a/", "/user/project/", "/whatever",     "/user/project/filename.php", "/var/a/filename.php"];
+    }
+}