Disk cache: Introduce BlockBitmaps for V3.

net/disk_cache/block_files.cc

Index: net/disk_cache/block_files.cc
===================================================================
--- net/disk_cache/block_files.cc	(revision 208788)
+++ net/disk_cache/block_files.cc	(working copy)
@@ -177,7 +177,7 @@
   }
 }
 
-bool BlockHeader::NeedToGrowBlockFile(int block_count) {
+bool BlockHeader::NeedToGrowBlockFile(int block_count) const {
   bool have_space = false;
   int empty_blocks = 0;
   for (int i = 0; i < kMaxNumBlocks; i++) {
@@ -195,6 +195,18 @@
   return !have_space;
 }
 
+bool BlockHeader::CanAllocate(int block_count) const {
+  bool have_space = false;
+  int empty_blocks = 0;
+  for (int i = 0; i < kMaxNumBlocks; i++) {
+    empty_blocks += header_->empty[i] * (i + 1);
+    if (i >= block_count - 1 && header_->empty[i])

[gavinp, 2013/06/27 07:06:18]

Nit: I'd find this more readable with () around block_count.

+      have_space = true;
+  }
+
+  return have_space;
+}
+
 int BlockHeader::EmptyBlocks() const {
   int empty_blocks = 0;
   for (int i = 0; i < disk_cache::kMaxNumBlocks; i++) {