From 5221eff69f918085b96e51b282d44d215ff04766 Mon Sep 17 00:00:00 2001
From: Zufu Liu <unknown>
Date: Fri, 6 Dec 2024 10:12:46 +1100
Subject: Feature [feature-requests:#1537]. Avoid truncation potential with
 PerformSort. Use string_view to improve safety.

---
 src/AutoComplete.cxx | 24 +++++++++++-------------
 src/AutoComplete.h   |  1 -
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/src/AutoComplete.cxx b/src/AutoComplete.cxx
index d49144684..57a3073f9 100644
--- a/src/AutoComplete.cxx
+++ b/src/AutoComplete.cxx
@@ -186,25 +186,23 @@ void AutoComplete::SetList(const char *list) {
 	}
 
 	std::string sortedList;
-	char item[maxItemLen];
 	for (size_t i = 0; i < sortMatrix.size(); ++i) {
-		int wordLen = IndexSort.indices[sortMatrix[i] * 2 + 2] - IndexSort.indices[sortMatrix[i] * 2];
-		if (wordLen > maxItemLen-2)
-			wordLen = maxItemLen - 2;
-		memcpy(item, list + IndexSort.indices[sortMatrix[i] * 2], wordLen);
-		if ((i+1) == sortMatrix.size()) {
+		const unsigned index = sortMatrix[i] * 2;
+		// word length include trailing typesep and separator
+		const int wordLen = IndexSort.indices[index + 2] - IndexSort.indices[index];
+		const std::string_view item(list + IndexSort.indices[index], wordLen);
+		sortedList += item;
+		if ((i + 1) == sortMatrix.size()) {
 			// Last item so remove separator if present
-			if ((wordLen > 0) && (item[wordLen-1] == separator))
-				wordLen--;
+			if (!item.empty() && item.back() == separator) {
+				sortedList.pop_back();
+			}
 		} else {
 			// Item before last needs a separator
-			if ((wordLen == 0) || (item[wordLen-1] != separator)) {
-				item[wordLen] = separator;
-				wordLen++;
+			if (item.empty() || item.back() != separator) {
+				sortedList += separator;
 			}
 		}
-		item[wordLen] = '\0';
-		sortedList += item;
 	}
 	for (int i = 0; i < static_cast<int>(sortMatrix.size()); ++i)
 		sortMatrix[i] = i;
diff --git a/src/AutoComplete.h b/src/AutoComplete.h
index 6afdf7c3e..ce8edd1d6 100644
--- a/src/AutoComplete.h
+++ b/src/AutoComplete.h
@@ -18,7 +18,6 @@ class AutoComplete {
 	std::string fillUpChars;
 	char separator;
 	char typesep; // Type separator
-	enum { maxItemLen=1000 };
 	std::vector<int> sortMatrix;
 
 public:
-- 
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