utils: Cache get_real_path to improve performance, make API more const

luehmann · Jun 7, 2014 · 4f4a051 · 4f4a051
1 parent d4ca613
commit 4f4a051
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/src/include/utils.hh b/src/include/utils.hh
@@ -143,7 +143,7 @@ std::list<std::string> split_string(const std::string &s, const char *delims);
 
 std::string trim_string(const std::string &strIn);
 
-std::string get_real_path(const std::string &path);
+const std::string &get_real_path(const std::string &path);
 
 bool string_is_integer(const std::string &str, unsigned base = 0);
 

diff --git a/src/utils.cc b/src/utils.cc
@@ -412,19 +412,24 @@ std::string trim_string(const std::string &strIn)
 	return str;
 }
 
-std::string get_real_path(const std::string &path)
+// Cache for ::realpath - it's apparently one of the reasons why kcov is slow
+static std::unordered_map<std::string, std::string> realPathCache;
+const std::string &get_real_path(const std::string &path)
 {
+	const auto &it = realPathCache.find(path);
+	if (it != realPathCache.end())
+		return it->second;
+
 	char *rp = NULL;
 
 	rp = ::realpath(path.c_str(), nullptr);
 
 	if (!rp)
 		return path;
 
-	std::string out(rp);
-	free(rp);
+	realPathCache[path] = rp;
 
-	return out;
+	return realPathCache[path];
 }