Implement text path trimming for shorter paths.

src/common/logging/text_formatter.h

@@ -12,6 +12,18 @@ namespace Log {
 class Logger;
 struct Entry;
 
+/**
+ * Attempts to trim an arbitrary prefix from `path`, leaving only the part starting at `root`. It's
+ * intended to be used to strip a system-specific build directory from the `__FILE__` macro,
+ * leaving only the path relative to the sources root.
+ *
+ * @param path The input file path as a null-terminated string
+ * @param root The name of the root source directory as a null-terminated string. Path up to and
+ *             including the last occurence of this name will be stripped
+ * @return A pointer to the same string passed as `path`, but starting at the trimmed portion
+ */
+const char* TrimSourcePath(const char* path, const char* root = "src");
+
 /// Formats a log entry into the provided text buffer.
 void FormatLogMessage(const Entry& entry, char* out_text, size_t text_len);
 /// Formats and prints a log entry to stderr.