SimpleCache: don't close sparse file when trying to close non-sparse one

(but still close it when closing them all)

Not sure if this could ever be hit IRL (testcase would check-fail on file
being invalid in File::Read off ReadSparseRange), but I am going to be
touching this for FD limits, and it helps if the code makes sense.

Bug: 636400
Change-Id: Ie33f1787a81f90b893d963e1fcb1db3b4fd0aab2
Reviewed-on: https://chromium-review.googlesource.com/652965
Commit-Queue: Maks Orlovich <morlovich@chromium.org>
Reviewed-by: Josh Karlin <jkarlin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506899}

net/disk_cache/entry_unittest.cc

@@ -4438,6 +4438,36 @@ TEST_F(DiskCacheEntryTest, SimpleCacheCreateCollision) {
   entry2->Close();
 }
 
+TEST_F(DiskCacheEntryTest, SimpleCacheConvertToSparseStream2LeftOver) {
+  // Testcase for what happens when we have a sparse stream and a left over
+  // empty stream 2 file.
+  const int kSize = 10;
+  scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(kSize));
+  CacheTestFillBuffer(buffer->data(), kSize, false);
+
+  SetSimpleCacheMode();
+  InitCache();
+  disk_cache::Entry* entry;
+  std::string key("a key");
+  ASSERT_THAT(CreateEntry(key, &entry), IsOk());
+  // Create an empty stream 2. To do that, we first make a non-empty one, then
+  // truncate it (since otherwise the write would just get ignored).
+  EXPECT_EQ(kSize, WriteData(entry, /* stream = */ 2, /* offset = */ 0,
+                             buffer.get(), kSize, false));
+  EXPECT_EQ(0, WriteData(entry, /* stream = */ 2, /* offset = */ 0,
+                         buffer.get(), 0, true));
+
+  EXPECT_EQ(kSize, WriteSparseData(entry, 5, buffer.get(), kSize));
+  entry->Close();
+
+  // Reopen, and try to get the sparse data back.
+  ASSERT_THAT(OpenEntry(key, &entry), IsOk());
+  scoped_refptr<net::IOBuffer> buffer2(new net::IOBuffer(kSize));
+  EXPECT_EQ(kSize, ReadSparseData(entry, 5, buffer2.get(), kSize));
+  EXPECT_EQ(0, memcmp(buffer->data(), buffer2->data(), kSize));
+  entry->Close();
+}
+
 class DiskCacheSimplePrefetchTest : public DiskCacheEntryTest {
  public:
   DiskCacheSimplePrefetchTest()

net/disk_cache/simple/simple_synchronous_entry.cc

@@ -1026,14 +1026,13 @@ void SimpleSynchronousEntry::CloseFile(int index) {
     DCHECK(files_[index].IsValid());
     files_[index].Close();
   }
-
-  if (sparse_file_open())
-    CloseSparseFile();
 }
 
 void SimpleSynchronousEntry::CloseFiles() {
   for (int i = 0; i < kSimpleEntryNormalFileCount; ++i)
     CloseFile(i);
+  if (sparse_file_open())
+    CloseSparseFile();
 }
 
 bool SimpleSynchronousEntry::CheckHeaderAndKey(int file_index) {