Rewrite git log parser (precise parsing)

Author: André L F S Bacci

scripts/translation/lib/GitSlowUtils.php

@@ -0,0 +1,103 @@
+<?php
+# +----------------------------------------------------------------------+
+# | Copyright (c) 1997-2024 The PHP Group                                |
+# +----------------------------------------------------------------------+
+# | This source file is subject to version 3.01 of the PHP license,      |
+# | that is bundled with this package in the file LICENSE, and is        |
+# | available through the world-wide-web at the following url:           |
+# | https://www.php.net/license/3_01.txt.                                |
+# | If you did not receive a copy of the PHP license and are unable to   |
+# | obtain it through the world-wide-web, please send a note to          |
+# | [email protected], so we can mail you a copy immediately.              |
+# +----------------------------------------------------------------------+
+# | Authors:     André L F S Bacci <ae php.net>                          |
+# +----------------------------------------------------------------------+
+# | Description: Common functions that interact with git command line.   |
+# +----------------------------------------------------------------------+
+
+require_once __DIR__ . '/all.php';
+
+class GitSlowUtils
+{
+    public static function checkDiffOnlyWsChange( string $gdir , RevcheckDataFile $file ) : bool
+    {
+        $hash = $file->hashRvtg;
+        $flnm = $file->path == "" ? $file->name : $file->path . "/" . $file->name;
+
+        $gdir = escapeshellarg( $gdir );
+        $flnm = escapeshellarg( $flnm );
+        $hash = escapeshellarg( $hash );
+
+        $func = '[' . __CLASS__ . ':' . __FUNCTION__ . ']';
+
+        // Fast path
+
+        // The git -b option is a bit misleading. It will ignore ws change
+        // on existing ws runs, but will report insertion or remotion of
+        // ws runs. This suffices for detecting significant ws changes and
+        // also ignoring insignificant ws changes in most cases we are
+        // interessed.
+
+        $output = `git -C $gdir diff -b $hash -- $flnm`;
+        $onlyws = $output == "";
+
+        // Slow path
+
+        if ( $onlyws )
+        {
+            $prev = `git -C $gdir show $hash:$flnm )`;
+            $next = `git -C $gdir show HEAD:$flnm )`;
+
+            if ( $prev == "" || $next == "" )
+            {
+                fprintf( STDERR , "$func Failed to read file contents.\n" );
+                return $onlyws;
+            }
+
+            $prev = GitUtils::discardPrefixSuffixEmptyWs( $prev );
+            $next = GitUtils::discardPrefixSuffixEmptyWs( $next );
+
+            if ( $prev != $next )
+            {
+                // Not really an error, but a theory. Report this bug/issue
+                // to start a discussion if this ws change must be ignored
+                // or tracked.
+
+                fprintf( STDERR , "$func Debug: Fast and slow path differ.\n" );
+                return false;
+            }
+        }
+
+        return $onlyws;
+    }
+
+    private static function discardPrefixSuffixEmptyWs( string $text ) : string
+    {
+        $lines = explode( "\n" , $text );
+        $trimLines = [];
+        foreach ( $lines as $line )
+            $trimLines[] = trim( $line );
+        return implode( "" , $trimLines );
+    }
+
+    public static function parseAddsDels( string $gdir , RevcheckDataFile $file )
+    {
+        $hash = $file->hashRvtg;
+        $name = $file->path == "" ? $file->name : $file->path . "/" . $file->name;
+
+        $gdir = escapeshellarg( $gdir );
+        $hash = escapeshellarg( $hash );
+        $name = escapeshellarg( $name );
+
+        $output = `git -C $gdir diff --numstat $hash -- $name`;
+        if ( $output )
+        {
+            preg_match( '/(\d+)\s+(\d+)/' , $output , $matches );
+            if ( $matches )
+            {
+                $file->adds = $matches[1];
+                $file->dels = $matches[2];
+            }
+        }
+    }
+}