Check last modified time in redex.

Summary: This used to be a condition in data pipeline. Now we want it to be configurable in redex.

Reviewed By: NTillmann

Differential Revision: D51815942

fbshipit-source-id: 00babf688dbd00d849aba1dc0603a8154493c216

libredex/ConfigFiles.cpp

@@ -351,18 +351,15 @@ void ConfigFiles::build_dead_class_and_live_class_split_lists() {
         DeadClassLoadCounts load_counts;
         StringTabSplitter splitter(line);
         std::string_view classname = splitter.get();
-        if (splitter.next()) {
-          std::string_view str = splitter.get();
-          from_chars(str, &load_counts.sampled);
-          if (splitter.next()) {
-            str = splitter.get();
-            from_chars(str, &load_counts.unsampled);
-            if (splitter.next()) {
-              str = splitter.get();
-              from_chars(str, &load_counts.beta_unsampled);
-            }
-          }
+        const uint32_t k_num_remaining_columns = 4;
+        std::array<int64_t*, k_num_remaining_columns> columns = {
+            &load_counts.sampled, &load_counts.unsampled,
+            &load_counts.beta_unsampled, &load_counts.last_modified_count};
+        for (uint32_t i = 0; splitter.next() && i < k_num_remaining_columns;
+             i++) {
+          from_chars(splitter.get(), columns[i]);
         }
+
         bool is_relocated = is_relocated_class(classname);
         if (is_relocated) {
           remove_relocated_part(&classname);

libredex/ConfigFiles.h

@@ -98,6 +98,9 @@ struct ConfigFiles {
     int64_t sampled{50}; // legacy
     int64_t unsampled{0};
     int64_t beta_unsampled{0}; // Whether is beta sample or not
+    int64_t last_modified_count{1}; // number of times that last modified time
+                                    // fall into acceptable range. Default value
+                                    // 1 is for backward compatibility.
   };
 
   const std::unordered_map<std::string, DeadClassLoadCounts>&