Disk cache: Make sure we don't overwrite external files when creating new ones.

TEST=unit test


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1270 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 27 insertions, 2 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index 9b15d5e..6abcd94c 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -576,7 +576,7 @@ bool BackendImpl::CreateExternalFile(Addr* address) {
   int file_number = data_->header.last_file + 1;
   Addr file_address(0);
   bool success = false;
-  for (int i = 0; (i < 0x0fffffff) && !success; i++) {
+  for (int i = 0; (i < 0x0fffffff) && !success; i++, file_number++) {
     if (!file_address.SetFileNumber(file_number)) {
       file_number = 1;
       continue;
@@ -584,7 +584,7 @@ bool BackendImpl::CreateExternalFile(Addr* address) {
     std::wstring name = GetFileName(file_address);
     scoped_refptr<disk_cache::File> file(
         new disk_cache::File(CreateOSFile(name.c_str(), OS_FILE_READ |
-            OS_FILE_WRITE |OS_FILE_SHARE_READ | OS_FILE_CREATE_ALWAYS, NULL)));
+            OS_FILE_WRITE |OS_FILE_SHARE_READ | OS_FILE_CREATE, NULL)));
     if (!file->IsValid())
       continue;
 
diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index cbdc450..661e52f 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -223,6 +223,29 @@ TEST_F(DiskCacheBackendTest, MemoryOnlyKeying) {
   BackendKeying();
 }
 
+TEST_F(DiskCacheBackendTest, ExternalFiles) {
+  InitCache();
+  // First, lets create a file on the folder.
+  std::wstring filename = GetCachePath();
+  file_util::AppendToPath(&filename, L"f_000001");
+
+  const int kDataSize = 50;
+  char data[kDataSize];
+  CacheTestFillBuffer(data, kDataSize, false);
+  ASSERT_EQ(kDataSize, file_util::WriteFile(filename, data, kDataSize));
+
+  // Now let's create a file with the cache.
+  disk_cache::Entry* entry;
+  ASSERT_TRUE(cache_->CreateEntry("key", &entry));
+  ASSERT_EQ(0, entry->WriteData(0, 20000, data, 0, NULL, false));
+  entry->Close();
+
+  // And verify that the first file is still there.
+  char buffer[kDataSize];
+  ASSERT_EQ(kDataSize, file_util::ReadFile(filename, buffer, kDataSize));
+  EXPECT_EQ(0, memcmp(data, buffer, kDataSize));
+}
+
 void DiskCacheBackendTest::BackendSetSize() {
   SetDirectMode();
   const int cache_size = 0x10000;  // 64 kB
diff --git a/net/disk_cache/entry_impl.cc b/net/disk_cache/entry_impl.cc
index 19dcae8..25c6236 100644
--- a/net/disk_cache/entry_impl.cc
+++ b/net/disk_cache/entry_impl.cc
@@ -331,6 +331,8 @@ int EntryImpl::WriteData(int index, int offset, const char* buf, int buf_len,
     unreported_size_[index] += offset + buf_len - entry_size;
     entry_.Data()->data_size[index] = offset + buf_len;
     entry_.set_modified();
+    if (!buf_len)
+      truncate = true;  // Force file extension.
   } else if (truncate) {
       // If the size was modified inside PrepareTarget, we should not do
       // anything here.