Add sensitize_strlit() for sanitizing C string literals

2 files changed, 36 insertions, 0 deletions

diff --git a/libbutl/utility.ixx b/libbutl/utility.ixx
index 27ef7fb..72fbc5b 100644
--- a/libbutl/utility.ixx
+++ b/libbutl/utility.ixx
@@ -219,6 +219,34 @@ namespace butl
     return sanitize_identifier (std::string (s));
   }
 
+  inline void
+  sanitize_strlit (const std::string& s, std::string& o)
+  {
+    for (size_t i (0), j;; i = j + 1)
+    {
+      j = s.find_first_of ("\\\"\n", i);
+      o.append (s.c_str () + i, (j == std::string::npos ? s.size () : j) - i);
+
+      if (j == std::string::npos)
+        break;
+
+      switch (s[j])
+      {
+      case '\\': o += "\\\\"; break;
+      case '"':  o += "\\\""; break;
+      case '\n': o += "\\n";  break;
+      }
+    }
+  }
+
+  inline std::string
+  sanitize_strlit (const std::string& s)
+  {
+    std::string r;
+    sanitize_strlit (s, r);
+    return r;
+  }
+
   inline bool
   eof (std::istream& is)
   {
diff --git a/libbutl/utility.mxx b/libbutl/utility.mxx
index b84e731..251471a 100644
--- a/libbutl/utility.mxx
+++ b/libbutl/utility.mxx
@@ -195,6 +195,14 @@ LIBBUTL_MODEXPORT namespace butl
   std::string  sanitize_identifier (std::string&&);
   std::string  sanitize_identifier (const std::string&);
 
+  // Sanitize a string (e.g., a path) to be a valid C string literal by
+  // escaping backslahes, double-quotes, and newlines.
+  //
+  // Note that in the second version the result is appended to out.
+  //
+  std::string sanitize_strlit (const std::string&);
+  void        sanitize_strlit (const std::string&, std::string& out);
+
   // Return true if the string is a valid UTF-8 encoded byte string and,
   // optionally, its decoded codepoints belong to the specified types or
   // codepoint whitelist.