Fix DirectoryCleaner sometimes deleting buck-out/log/ subdirectories for the current run

Summary: After it decides it needs to delete stuff, `DirectoryCleaner` doesn't respect `LogFileHandler`'s minimum number of logs to keep setting. When log subdirectories become relatively large, e.g. 10MB when outputting verbose rulekey logs, even the log subdirectories for the current run can get deleted, leaving behind dangling `last_XXXcommand` symlinks. The fix is to consolidate the deletion check logic in one place.

Reviewed By: styurin

fbshipit-source-id: 8660a1b5f2

Author: jtorkkola

src/com/facebook/buck/util/DirectoryCleaner.java

@@ -55,7 +55,7 @@ public void clean(Path pathToClean) throws IOException {
       pathStats.add(stats);
     }
 
-    if (shouldDeleteOldestLog(pathStats.size(), totalSizeBytes)) {
+    if (shouldDeleteOldestLog(pathStats.size(), totalSizeBytes, args.getMaxTotalSizeBytes())) {
       Collections.sort(
           pathStats, (stats1, stats2) -> args.getPathSelector().comparePaths(stats1, stats2));
 
@@ -66,8 +66,7 @@ public void clean(Path pathToClean) throws IOException {
       }
 
       for (int i = 0; i < pathStats.size(); ++i) {
-        if (totalSizeBytes <= finalMaxSizeBytes
-            && remainingLogDirectories <= args.getMaxPathCount()) {
+        if (!shouldDeleteOldestLog(remainingLogDirectories, totalSizeBytes, finalMaxSizeBytes)) {
           break;
         }
 
@@ -82,13 +81,13 @@ public void clean(Path pathToClean) throws IOException {
     }
   }
 
-  private boolean shouldDeleteOldestLog(int currentNumberOfLogs, long totalSizeBytes) {
+  private boolean shouldDeleteOldestLog(
+      int currentNumberOfLogs, long totalSizeBytes, long maxTotalSizeBytes) {
     if (currentNumberOfLogs <= args.getMinAmountOfEntriesToKeep()) {
       return false;
     }
 
-    return totalSizeBytes > args.getMaxTotalSizeBytes()
-        || currentNumberOfLogs > args.getMaxPathCount();
+    return totalSizeBytes > maxTotalSizeBytes || currentNumberOfLogs > args.getMaxPathCount();
   }
 
   private PathStats computePathStats(Path path) throws IOException {