build-system: Add ‘composer-build-system’.

* guix/build-system/composer.scm: New file.
* guix/build/composer-build-system.scm: New file.
* gnu/packages/aux-files/findclass.php: New file.
* Makefile.am: Add them.
* doc/guix.texi (Build Systems): Document it.

Co-authored-by: Julien Lepiller <julien@lepiller.eu>
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Change-Id: Ie6a05b42ff04d3ad774a0a20278a77e4820bb8f6

1 files changed, 125 insertions, 0 deletions

diff --git a/gnu/packages/aux-files/findclass.php b/gnu/packages/aux-files/findclass.php
new file mode 100644
index 0000000000..d0b250c8e1
--- /dev/null
+++ b/gnu/packages/aux-files/findclass.php
@@ -0,0 +1,125 @@
+<?php
+/**
+ * The content of this file is copied from composer's src/Composer/Autoload/ClassMapGenerator.php
+ * the findClasses method was extracted, to prevent using any dependency.
+ *
+ * Composer (and thus this file) is distributed under the expat license, and
+ * ClassMapGenerator.php also contains this notice:
+ *
+ *   This file is part of Composer.
+ *
+ *   (c) Nils Adermann <naderman@naderman.de>
+ *       Jordi Boggiano <j.boggiano@seld.be>
+ *
+ *   For the full copyright and license information, please view the LICENSE
+ *   file that was distributed with this source code.
+ *
+ *   This file is copied from the Symfony package.
+ *
+ *   (c) Fabien Potencier <fabien@symfony.com>
+ * 
+ * To the extent to wich it makes sense, as the author of the extract:
+ * Copyright © 2020 Julien Lepiller <julien@lepiller.eu>
+ */
+
+/**
+ * Extract the classes in the given file
+ *
+ * @param  string            $path The file to check
+ * @throws \RuntimeException
+ * @return array             The found classes
+ */
+function findClasses($path)
+{
+    $extraTypes = PHP_VERSION_ID < 50400 ? '' : '|trait';
+    if (defined('HHVM_VERSION') && version_compare(HHVM_VERSION, '3.3', '>=')) {
+        $extraTypes .= '|enum';
+    }
+    // Use @ here instead of Silencer to actively suppress 'unhelpful' output
+    // @link https://github.com/composer/composer/pull/4886
+    $contents = @php_strip_whitespace($path);
+    if (!$contents) {
+        if (!file_exists($path)) {
+            $message = 'File at "%s" does not exist, check your classmap definitions';
+        } elseif (!is_readable($path)) {
+            $message = 'File at "%s" is not readable, check its permissions';
+        } elseif ('' === trim(file_get_contents($path))) {
+            // The input file was really empty and thus contains no classes
+            return array();
+        } else {
+            $message = 'File at "%s" could not be parsed as PHP, it may be binary or corrupted';
+        }
+        $error = error_get_last();
+        if (isset($error['message'])) {
+            $message .= PHP_EOL . 'The following message may be helpful:' . PHP_EOL . $error['message'];
+        }
+        throw new \RuntimeException(sprintf($message, $path));
+    }
+    // return early if there is no chance of matching anything in this file
+    if (!preg_match('{\b(?:class|interface'.$extraTypes.')\s}i', $contents)) {
+        return array();
+    }
+    // strip heredocs/nowdocs
+    $contents = preg_replace('{<<<[ \t]*([\'"]?)(\w+)\\1(?:\r\n|\n|\r)(?:.*?)(?:\r\n|\n|\r)(?:\s*)\\2(?=\s+|[;,.)])}s', 'null', $contents);
+    // strip strings
+    $contents = preg_replace('{"[^"\\\\]*+(\\\\.[^"\\\\]*+)*+"|\'[^\'\\\\]*+(\\\\.[^\'\\\\]*+)*+\'}s', 'null', $contents);
+    // strip leading non-php code if needed
+    if (substr($contents, 0, 2) !== '<?') {
+        $contents = preg_replace('{^.+?<\?}s', '<?', $contents, 1, $replacements);
+        if ($replacements === 0) {
+            return array();
+        }
+    }
+    // strip non-php blocks in the file
+    $contents = preg_replace('{\?>(?:[^<]++|<(?!\?))*+<\?}s', '?><?', $contents);
+    // strip trailing non-php code if needed
+    $pos = strrpos($contents, '?>');
+    if (false !== $pos && false === strpos(substr($contents, $pos), '<?')) {
+        $contents = substr($contents, 0, $pos);
+    }
+    // strip comments if short open tags are in the file
+    if (preg_match('{(<\?)(?!(php|hh))}i', $contents)) {
+        $contents = preg_replace('{//.* | /\*(?:[^*]++|\*(?!/))*\*/}x', '', $contents);
+    }
+    preg_match_all('{
+        (?:
+             \b(?<![\$:>])(?P<type>class|interface'.$extraTypes.') \s++ (?P<name>[a-zA-Z_\x7f-\xff:][a-zA-Z0-9_\x7f-\xff:\-]*+)
+           | \b(?<![\$:>])(?P<ns>namespace) (?P<nsname>\s++[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*+(?:\s*+\\\\\s*+[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*+)*+)? \s*+ [\{;]
+        )
+    }ix', $contents, $matches);
+    $classes = array();
+    $namespace = '';
+    for ($i = 0, $len = count($matches['type']); $i < $len; $i++) {
+        if (!empty($matches['ns'][$i])) {
+            $namespace = str_replace(array(' ', "\t", "\r", "\n"), '', $matches['nsname'][$i]) . '\\';
+        } else {
+            $name = $matches['name'][$i];
+            // skip anon classes extending/implementing
+            if ($name === 'extends' || $name === 'implements') {
+                continue;
+            }
+            if ($name[0] === ':') {
+                // This is an XHP class, https://github.com/facebook/xhp
+                $name = 'xhp'.substr(str_replace(array('-', ':'), array('_', '__'), $name), 1);
+            } elseif ($matches['type'][$i] === 'enum') {
+                // In Hack, something like:
+                //   enum Foo: int { HERP = '123'; }
+                // The regex above captures the colon, which isn't part of
+                // the class name.
+                $name = rtrim($name, ':');
+            }
+            $classes[] = ltrim($namespace . $name, '\\');
+        }
+    }
+    return $classes;
+}
+
+$options = getopt('i:f:', []);
+$file = $options["f"];
+$input = $options["i"];
+
+$classes = findClasses($file);
+foreach($classes as $class) {
+  echo '$classmap[\''.$class.'\'] = \''.$input.'/'.$file.'\';';
+  echo "\n";
+}