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 208996)
+++ 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])
+      have_space = true;
+  }
+
+  return have_space;
+}
+
 int BlockHeader::EmptyBlocks() const {
   int empty_blocks = 0;
   for (int i = 0; i < disk_cache::kMaxNumBlocks; i++) {
@@ -260,7 +272,7 @@
 
 MappedFile* BlockFiles::GetFile(Addr address) {
   DCHECK(thread_checker_->CalledOnValidThread());
-  DCHECK(block_files_.size() >= 4);
+  DCHECK(block_files_.size() >= kFirstAdditionalBlockFile);

[gavinp, 2013/06/28 21:47:45]

Nit: Consider using the DCHECK_LE macro here, and many other places through this
CL.

[rvargas (doing something else), 2013/07/11 19:54:55]

Already changed

   DCHECK(address.is_block_file() || !address.is_initialized());
   if (!address.is_initialized())
     return NULL;
@@ -280,8 +292,9 @@
                              Addr* block_address) {
   DCHECK(thread_checker_->CalledOnValidThread());
   if (block_type < RANKINGS || block_type > BLOCK_4K ||
-      block_count < 1 || block_count > 4)
+      block_count < 1 || block_count > kMaxNumBlocks) {
     return false;
+  }
   if (!init_)
     return false;
 
@@ -293,7 +306,7 @@
   BlockHeader header(file);
 
   int target_size = 0;
-  for (int i = block_count; i <= 4; i++) {
+  for (int i = block_count; i <= kMaxNumBlocks; i++) {
     if (header->empty[i - 1]) {
       target_size = i;
       break;
@@ -671,7 +684,7 @@
 
     max_blocks += header->max_entries;
     int used = header->max_entries;
-    for (int i = 0; i < 4; i++) {
+    for (int i = 0; i < kMaxNumBlocks; i++) {
       used -= header->empty[i] * (i + 1);
       DCHECK_GE(used, 0);
     }