Disk Based Certificate Cache Implementation

net/http/disk_based_cert_cache.cc

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/http/disk_based_cert_cache.h"
+
+#include <string>

[wtc, 2014/06/12 03:13:16]

Nit: since the .h file includes <string>, the .cc file doesn't need to include
it again.

+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/callback_helpers.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/strings/string_number_conversions.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/cert/x509_certificate.h"
+#include "net/disk_cache/disk_cache.h"

[wtc, 2014/06/12 03:13:16]

The headers that are included by the .h file don't need to be included again.

+
+namespace net {
+
+DiskBasedCertCache::DiskBasedCertCache(disk_cache::Backend* backend)
+    : backend_(backend),
+      active_entry_(NULL),
+      state_(NONE),
+      create_failed_(false),
+      active_entry_size_(0),
+      weak_factory_(this) {
+  DCHECK(backend_);
+  io_callback_ =
+      base::Bind(&DiskBasedCertCache::OnIOComplete, weak_factory_.GetWeakPtr());
+}
+
+DiskBasedCertCache::~DiskBasedCertCache() {
+  weak_factory_.InvalidateWeakPtrs();
+}
+
+void DiskBasedCertCache::Get(
+    std::string& key,
+    base::Callback<void(X509Certificate::OSCertHandle cert_handle)> cb) {
+  user_read_callback_ = cb;
+
+  state_ = START_READ;
+
+  int rv = backend_->OpenEntry(key, &active_entry_, io_callback_);
+
+  DoLoop(rv);
+}
+
+int DiskBasedCertCache::DoStartRead(int rv) {
+  // todo(brandonsalmon) implement error handling

[wtc, 2014/06/12 03:13:16]

Our convention is all caps TODO.

+  if (rv <= 0)
+    NOTIMPLEMENTED();
+
+  active_entry_size_ = active_entry_->GetDataSize(0 /* index */);
+  buffer = new IOBuffer(active_entry_size_);
+
+  state_ = FINISH_READ;
+
+  return active_entry_->ReadData(
+      0 /* index */, 0 /* offset */, buffer, active_entry_size_, io_callback_);
+}
+
+int DiskBasedCertCache::DoFinishRead(int rv) {
+  // todo(brandonsalmon) implement error handling
+  if (rv <= 0)
+    NOTIMPLEMENTED();
+
+  if (user_read_callback_.is_null()) {
+    ResetState();
+    return OK;  // todo(brandonsalmon): is this ERR_ABORTED?
+  }
+
+  active_cert_handle_ = X509Certificate::CreateOSCertHandleFromBytes(
+      buffer->data(), active_entry_size_);
+
+  CHECK(active_cert_handle_);
+
+  base::ResetAndReturn(&user_read_callback_).Run(active_cert_handle_);
+
+  ResetState();
+  return OK;
+}
+
+void DiskBasedCertCache::Set(const X509Certificate::OSCertHandle cert_handle,
+                             base::Callback<void(const std::string&)> cb) {
+  DCHECK(!cb.is_null());
+
+  active_cert_handle_ = cert_handle;
+
+  state_ = CREATE_OR_OPEN;
+  user_write_callback_ = cb;
+  DoLoop(OK);
+}
+
+std::string DiskBasedCertCache::Key() {
+  CHECK(active_cert_handle_);
+
+  SHA1HashValue fingerprint =
+      X509Certificate::CalculateFingerprint(active_cert_handle_);
+
+  // should update to store the key so the data doesn't have to be encoded
+  // multiple times.
+
+  return "cert:" + base::HexEncode(fingerprint.data, 20);

[wtc, 2014/06/12 03:13:16]

Avoid the use of 20. Try arraysize(fingerprint.data).

+}
+
+void DiskBasedCertCache::DoLoop(int rv) {
+  do {
+    switch (state_) {
+      case CREATE_OR_OPEN:
+        rv = DoCreateOrOpen(rv);
+        break;
+      case START_WRITE:
+        rv = DoStartWrite(rv);
+        break;
+      case FINISH_CREATE_OR_OPEN:
+        rv = DoFinishCreateOrOpen(rv);
+        break;
+      case FINISH_WRITE:
+        rv = DoFinishWrite(rv);
+        break;
+      case START_READ:
+        rv = DoStartRead(rv);
+        break;
+      case FINISH_READ:
+        rv = DoFinishRead(rv);
+        break;
+      case NONE:
+        break;
+    }
+  } while (rv != ERR_IO_PENDING && state_ != NONE);
+}
+
+void DiskBasedCertCache::OnIOComplete(int rv) {
+  // todo(brandonsalmon) Check for fatal errors?
+  DoLoop(rv);
+}
+
+int DiskBasedCertCache::DoStartWrite(int rv) {
+  // todo(brandonsalmon) implement error handling
+  if (rv <= 0)
+    NOTIMPLEMENTED();
+
+  std::string write_data;
+  // todo(brandonsalmon) deal with faulty encoding.
+  bool encoded =
+      X509Certificate::GetDEREncoded(active_cert_handle_, &write_data);
+
+  if (!encoded)
+    NOTIMPLEMENTED();
+
+  buffer = new IOBuffer(write_data.size());
+  memcpy(buffer->data(), write_data.data(), write_data.size());
+
+  state_ = FINISH_WRITE;
+
+  return active_entry_->WriteData(0 /* index */,
+                                  0 /* offset */,
+                                  buffer,
+                                  write_data.size(),
+                                  io_callback_,
+                                  true /* truncate */);
+}
+
+int DiskBasedCertCache::DoCreateOrOpen(int rv) {
+  DCHECK(active_entry_ == NULL);
+
+  state_ = FINISH_CREATE_OR_OPEN;
+
+  if (create_failed_) {
+    return backend_->OpenEntry(Key(), &active_entry_, io_callback_);
+  }
+
+  return backend_->CreateEntry(Key(), &active_entry_, io_callback_);
+}
+
+int DiskBasedCertCache::DoFinishCreateOrOpen(int rv) {
+  // ERR_FAILED implies create entry failed, and we should try opening instead.
+  //!create_failed is checked to make sure we only try to open once.
+  if (rv == ERR_FAILED && !create_failed_) {
+    create_failed_ = true;
+    state_ = CREATE_OR_OPEN;
+    return OK;
+  } else if (rv <= 0) {
+    NOTIMPLEMENTED();
+  }
+
+  state_ = START_WRITE;
+  return OK;
+}
+
+int DiskBasedCertCache::DoFinishWrite(int rv) {
+  // todo(brandonsalmon) implement error handling
+  if (rv <= 0)
+    NOTIMPLEMENTED();
+
+  if (user_write_callback_.is_null()) {
+    ResetState();
+    return OK;  // todo(brandonsalmon): is this ERR_ABORTED?
+  }
+
+  base::ResetAndReturn(&user_write_callback_).Run(Key());
+  ResetState();
+  return OK;
+}
+
+void DiskBasedCertCache::ResetState() {
+  state_ = NONE;
+  active_entry_->Close();
+  active_entry_ = NULL;
+  active_cert_handle_ = NULL;
+  user_write_callback_.Reset();
+  user_read_callback_.Reset();
+}
+
+}  // namespace net