Add file modification history update script

scripts/updateModHistory.php

@@ -0,0 +1,123 @@
+<?php
+
+$modHistoryFile = 'fileModHistory.php';
+
+$modHistoryArray = [];
+if (file_exists($modHistoryFile)) {
+    $modHistoryArray = include $modHistoryFile;
+    if (!is_array($modHistoryArray)) {
+        exit("Corrupted modificiation history file\n");
+    }
+}
+
+if (isset($modHistoryArray["last commit hash"]) && $modHistoryArray["last commit hash"] !== "") {
+    $cmd = "git rev-parse --quiet --verify " . $modHistoryArray["last commit hash"];
+    if (exec($cmd, $verifiedHash) === false) {
+        exit("Could not retrieve hash of the last commit\n");
+    }
+    if (implode("", $verifiedHash) !== $modHistoryArray["last commit hash"]) {
+        // we cannot handle reverted commits as we don't know what changes to roll back
+        exit("Modification history file's commit hash is not in this branch's commit history\n");
+    }
+    $lastCommitHash = $modHistoryArray["last commit hash"];
+} else {
+    // since there is no modification history, generate it for all commits since the inital one
+    // 4b825dc642cb6eb9a060e54bf8d69288fbee4904 is the SHA1 of the empty git tree
+    $lastCommitHash = "4b825dc642cb6eb9a060e54bf8d69288fbee4904";
+}
+
+$modifiedFilescommand = <<<COMMAND
+#!/usr/bin/env bash
+echo "last commit hash:"
+echo "$(git rev-parse HEAD)"
+git diff --name-only HEAD $lastCommitHash | while read -r filename; do
+  echo "filename:"
+  echo "\$filename"
+  echo "modified:"
+  echo "$(git log -1 --format='%aI' -- \$filename)"
+  echo "contributors:"
+  git log --format='%an' -- \$filename|awk '!a[$0]++'
+done
+COMMAND;
+
+if (exec($modifiedFilescommand, $output) === false) {
+    exit("Could not retrieve info from last commit\n");
+}
+
+$modifiedFiles = [];
+$currentType = "";
+foreach ($output as $line) {
+    switch ($line) {
+        case "filename:":
+            $currentType = "filename";
+            continue 2;
+        case "modified:":
+            $currentType = "modDateTime";
+            continue 2;
+        case "contributors:":
+            $currentType = "contributors";
+            continue 2;
+        case "last commit hash:":
+            $currentType = "commitHash";
+            continue 2;
+    }
+    if ($currentType === "") {
+        continue;
+    }
+
+    switch ($currentType) {
+        case "filename":
+            $currentFile = $line;
+            break;
+        case "modDateTime":
+            if ($currentFile === "") {
+                continue 2;
+            }
+            $modifiedFiles[$currentFile]["modified"] = $line;
+            break;
+        case "contributors":
+            if ($currentFile === "") {
+                continue 2;
+            }
+            $modifiedFiles[$currentFile]["contributors"][] = htmlspecialchars($line, ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401);
+            break;
+        case "commitHash":
+            $modifiedFiles["last commit hash"][] = $line;
+            break;
+    }
+}
+
+if (count($modifiedFiles) === 1) {
+    // there will always be 1 entry with the last commit hash
+    exit("No files have been modified\n");
+}
+
+$mergedModHistory = array_merge($modHistoryArray, $modifiedFiles);
+
+$newModHistoryString = "<?php\n\n/* This is a generated file */\n\nreturn [\n";
+foreach ($mergedModHistory as $fileName => $fileProps) {
+    if ($fileName === "last commit hash") {
+        $newModHistoryString .= "    \"last commit hash\" => \"" . implode("", $fileProps) . "\",\n";
+        continue;
+    }
+    $newModHistoryString .= '    "' . $fileName . "\" => [\n";
+    $newModHistoryString .= "        \"modified\" => \"" . ($fileProps["modified"] ?? "") . "\",\n";
+    $newModHistoryString .= "        \"contributors\" => [\n";
+    if (isset($fileProps["contributors"])) {
+        if (!is_array($fileProps["contributors"])) {
+            exit("Non-array contributors list\n");
+        }
+        foreach ($fileProps["contributors"] as $contributor) {
+            $newModHistoryString .= "            \"" . $contributor . "\",\n";
+        }
+    }
+    $newModHistoryString .= "        ],\n";
+    $newModHistoryString .= "    ],\n";
+}
+$newModHistoryString .= "];\n";
+
+if (file_put_contents($modHistoryFile, $newModHistoryString) === false) {
+    exit("Could not write modification history file\n");
+}
+
+echo "Modification history updated\n";