GitInfo.php

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<?php
use MediaWiki\Shell\Shell;

class GitInfo {

    protected static $repo = null;

    protected $basedir;

    protected $repoDir;

    protected $cacheFile;

    protected $cache = [];

    private static $viewers = false;

    public function __construct( $repoDir, $usePrecomputed = true ) {
        $this->repoDir = $repoDir;
        $this->cacheFile = self::getCacheFilePath( $repoDir );
        wfDebugLog( 'gitinfo',
            "Candidate cacheFile={$this->cacheFile} for {$repoDir}"
        );
        if ( $usePrecomputed &&
            $this->cacheFile !== null &&
            is_readable( $this->cacheFile )
        ) {
            $this->cache = FormatJson::decode(
                file_get_contents( $this->cacheFile ),
                true
            );
            wfDebugLog( 'gitinfo', "Loaded git data from cache for {$repoDir}" );
        }

        if ( !$this->cacheIsComplete() ) {
            wfDebugLog( 'gitinfo', "Cache incomplete for {$repoDir}" );
            $this->basedir = $repoDir . DIRECTORY_SEPARATOR . '.git';
            if ( is_readable( $this->basedir ) && !is_dir( $this->basedir ) ) {
                $GITfile = file_get_contents( $this->basedir );
                if ( strlen( $GITfile ) > 8 &&
                    substr( $GITfile, 0, 8 ) === 'gitdir: '
                ) {
                    $path = rtrim( substr( $GITfile, 8 ), "\r\n" );
                    if ( $path[0] === '/' || substr( $path, 1, 1 ) === ':' ) {
                        // Path from GITfile is absolute
                        $this->basedir = $path;
                    } else {
                        $this->basedir = $repoDir . DIRECTORY_SEPARATOR . $path;
                    }
                }
            }
        }
    }

    protected static function getCacheFilePath( $repoDir ) {
        global $IP, $wgGitInfoCacheDirectory;

        if ( $wgGitInfoCacheDirectory ) {
            // Convert both $IP and $repoDir to canonical paths to protect against
            // $IP having changed between the settings files and runtime.
            $realIP = realpath( $IP );
            $repoName = realpath( $repoDir );
            if ( $repoName === false ) {
                // Unit tests use fake path names
                $repoName = $repoDir;
            }
            if ( strpos( $repoName, $realIP ) === 0 ) {
                // Strip $IP from path
                $repoName = substr( $repoName, strlen( $realIP ) );
            }
            // Transform path to git repo to something we can safely embed in
            // a filename
            $repoName = strtr( $repoName, DIRECTORY_SEPARATOR, '-' );
            $fileName = 'info' . $repoName . '.json';
            $cachePath = "{$wgGitInfoCacheDirectory}/{$fileName}";
            if ( is_readable( $cachePath ) ) {
                return $cachePath;
            }
        }

        return "$repoDir/gitinfo.json";
    }

    public static function repo() {
        if ( is_null( self::$repo ) ) {
            global $IP;
            self::$repo = new self( $IP );
        }
        return self::$repo;
    }

    public static function isSHA1( $str ) {
        return (bool)preg_match( '/^[0-9A-F]{40}$/i', $str );
    }

    public function getHead() {
        if ( !isset( $this->cache['head'] ) ) {
            $headFile = "{$this->basedir}/HEAD";
            $head = false;

            if ( is_readable( $headFile ) ) {
                $head = file_get_contents( $headFile );

                if ( preg_match( "/ref: (.*)/", $head, $m ) ) {
                    $head = rtrim( $m[1] );
                } else {
                    $head = rtrim( $head );
                }
            }
            $this->cache['head'] = $head;
        }
        return $this->cache['head'];
    }

    public function getHeadSHA1() {
        if ( !isset( $this->cache['headSHA1'] ) ) {
            $head = $this->getHead();
            $sha1 = false;

            // If detached HEAD may be a SHA1
            if ( self::isSHA1( $head ) ) {
                $sha1 = $head;
            } else {
                // If not a SHA1 it may be a ref:
                $refFile = "{$this->basedir}/{$head}";
                $packedRefs = "{$this->basedir}/packed-refs";
                $headRegex = preg_quote( $head, '/' );
                if ( is_readable( $refFile ) ) {
                    $sha1 = rtrim( file_get_contents( $refFile ) );
                } elseif ( is_readable( $packedRefs ) &&
                    preg_match( "/^([0-9A-Fa-f]{40}) $headRegex$/m", file_get_contents( $packedRefs ), $matches )
                ) {
                    $sha1 = $matches[1];
                }
            }
            $this->cache['headSHA1'] = $sha1;
        }
        return $this->cache['headSHA1'];
    }

    public function getHeadCommitDate() {
        global $wgGitBin;

        if ( !isset( $this->cache['headCommitDate'] ) ) {
            $date = false;
            if ( is_file( $wgGitBin ) &&
                is_executable( $wgGitBin ) &&
                !Shell::isDisabled() &&
                $this->getHead() !== false
            ) {
                $cmd = [
                    $wgGitBin,
                    'show',
                    '-s',
                    '--format=format:%ct',
                    'HEAD',
                ];
                $gitDir = realpath( $this->basedir );
                $result = Shell::command( $cmd )
                    ->environment( [ 'GIT_DIR' => $gitDir ] )
                    ->restrict( Shell::RESTRICT_DEFAULT | Shell::NO_NETWORK )
                    ->whitelistPaths( [ $gitDir, $this->repoDir ] )
                    ->execute();

                if ( $result->getExitCode() === 0 ) {
                    $date = (int)$result->getStdout();
                }
            }
            $this->cache['headCommitDate'] = $date;
        }
        return $this->cache['headCommitDate'];
    }

    public function getCurrentBranch() {
        if ( !isset( $this->cache['branch'] ) ) {
            $branch = $this->getHead();
            if ( $branch &&
                preg_match( "#^refs/heads/(.*)$#", $branch, $m )
            ) {
                $branch = $m[1];
            }
            $this->cache['branch'] = $branch;
        }
        return $this->cache['branch'];
    }

    public function getHeadViewUrl() {
        $url = $this->getRemoteUrl();
        if ( $url === false ) {
            return false;
        }
        foreach ( self::getViewers() as $repo => $viewer ) {
            $pattern = '#^' . $repo . '$#';
            if ( preg_match( $pattern, $url, $matches ) ) {
                $viewerUrl = preg_replace( $pattern, $viewer, $url );
                $headSHA1 = $this->getHeadSHA1();
                $replacements = [
                    '%h' => substr( $headSHA1, 0, 7 ),
                    '%H' => $headSHA1,
                    '%r' => urlencode( $matches[1] ),
                    '%R' => $matches[1],
                ];
                return strtr( $viewerUrl, $replacements );
            }
        }
        return false;
    }

    protected function getRemoteUrl() {
        if ( !isset( $this->cache['remoteURL'] ) ) {
            $config = "{$this->basedir}/config";
            $url = false;
            if ( is_readable( $config ) ) {
                Wikimedia\suppressWarnings();
                $configArray = parse_ini_file( $config, true );
                Wikimedia\restoreWarnings();
                $remote = false;

                // Use the "origin" remote repo if available or any other repo if not.
                if ( isset( $configArray['remote origin'] ) ) {
                    $remote = $configArray['remote origin'];
                } elseif ( is_array( $configArray ) ) {
                    foreach ( $configArray as $sectionName => $sectionConf ) {
                        if ( substr( $sectionName, 0, 6 ) == 'remote' ) {
                            $remote = $sectionConf;
                        }
                    }
                }

                if ( $remote !== false && isset( $remote['url'] ) ) {
                    $url = $remote['url'];
                }
            }
            $this->cache['remoteURL'] = $url;
        }
        return $this->cache['remoteURL'];
    }

    public function cacheIsComplete() {
        return isset( $this->cache['head'] ) &&
            isset( $this->cache['headSHA1'] ) &&
            isset( $this->cache['headCommitDate'] ) &&
            isset( $this->cache['branch'] ) &&
            isset( $this->cache['remoteURL'] );
    }

    public function precomputeValues() {
        if ( $this->cacheFile !== null ) {
            // Try to completely populate the cache
            $this->getHead();
            $this->getHeadSHA1();
            $this->getHeadCommitDate();
            $this->getCurrentBranch();
            $this->getRemoteUrl();

            if ( !$this->cacheIsComplete() ) {
                wfDebugLog( 'gitinfo',
                    "Failed to compute GitInfo for \"{$this->basedir}\""
                );
                return;
            }

            $cacheDir = dirname( $this->cacheFile );
            if ( !file_exists( $cacheDir ) &&
                !wfMkdirParents( $cacheDir, null, __METHOD__ )
            ) {
                throw new MWException( "Unable to create GitInfo cache \"{$cacheDir}\"" );
            }

            file_put_contents( $this->cacheFile, FormatJson::encode( $this->cache ) );
        }
    }

    public static function headSHA1() {
        return self::repo()->getHeadSHA1();
    }

    public static function currentBranch() {
        return self::repo()->getCurrentBranch();
    }

    public static function headViewUrl() {
        return self::repo()->getHeadViewUrl();
    }

    protected static function getViewers() {
        global $wgGitRepositoryViewers;

        if ( self::$viewers === false ) {
            self::$viewers = $wgGitRepositoryViewers;
            Hooks::run( 'GitViewers', [ &self::$viewers ] );
        }

        return self::$viewers;
    }
}