Color: Separate ICCProfile and ColorSpace structures

ui/gfx/icc_profile.cc

Index: ui/gfx/icc_profile.cc
diff --git a/ui/gfx/icc_profile.cc b/ui/gfx/icc_profile.cc
new file mode 100644
index 0000000000000000000000000000000000000000..da49f0e8ed006ec68206f052680922f9afda356d
--- /dev/null
+++ b/ui/gfx/icc_profile.cc
@@ -0,0 +1,126 @@
+// Copyright 2016 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 "ui/gfx/icc_profile.h"
+
+#include <list>
+
+#include "base/containers/mru_cache.h"
+#include "base/lazy_instance.h"
+#include "base/synchronization/lock.h"
+
+namespace gfx {
+
+namespace {
+const size_t kMinProfileLength = 128;
+const size_t kMaxProfileLength = 4 * 1024 * 1024;
+
+// Allow keeping around a maximum of 8 cached ICC profiles. Beware that
+// we will do a linear search thorugh currently-cached ICC profiles,
+// when creating a new ICC profile.
+const size_t kMaxCachedICCProfiles = 8;
+
+struct Cache {
+  Cache() : id_to_icc_profile_mru(kMaxCachedICCProfiles) {}
+  ~Cache() {}
+
+  // Start from-ICC-data IDs at the end of the hard-coded list.
+  uint64_t next_unused_id = 5;

[dcheng, 2016/07/25 13:42:26]

Dumb question: how do the initial hardcoded entries get into the cache? Or do
they have a completely separate path? Or is this part of the TODO noted in
FromColorspace?

[ccameron, 2016/07/25 21:31:54]

They're part of the TODO -- we don't compute them yet.

+  base::MRUCache<uint64_t, ICCProfile> id_to_icc_profile_mru;
+  base::Lock lock;
+};
+static base::LazyInstance<Cache> g_cache;
+
+}  // namespace
+
+ICCProfile::ICCProfile() = default;
+ICCProfile::ICCProfile(ICCProfile&& other) = default;
+ICCProfile::ICCProfile(const ICCProfile& other) = default;
+ICCProfile& ICCProfile::operator=(const ICCProfile& other) = default;
+ICCProfile::~ICCProfile() = default;
+
+bool ICCProfile::operator==(const ICCProfile& other) const {
+  return valid_ == other.valid_ && data_ == other.data_;
+}
+
+// static
+ICCProfile ICCProfile::FromData(const std::vector<char>& icc_profile_data) {
+  ICCProfile icc_profile;
+  if (IsValidProfileLength(icc_profile_data.size())) {
+    icc_profile.valid_ = true;
+    icc_profile.data_ = icc_profile_data;
+  }
+  if (!icc_profile.valid_)
+    return icc_profile;
+
+  Cache& cache = g_cache.Get();
+  base::AutoLock lock(cache.lock);
+
+  // Linearly search the cached ICC profiles to find one with the same data.
+  // If it exists, re-use its id and touch it in the cache.
+  for (auto iter = cache.id_to_icc_profile_mru.begin();
+       iter != cache.id_to_icc_profile_mru.end(); ++iter) {
+    if (icc_profile.data_ == iter->second.data_) {
+      icc_profile.id_ = iter->second.id_;
+      cache.id_to_icc_profile_mru.Get(icc_profile.id_);
+      return icc_profile;
+    }
+  }
+
+  // Create a new cached id and add it to the cache.
+  icc_profile.id_ = cache.next_unused_id++;
+  cache.id_to_icc_profile_mru.Put(icc_profile.id_, icc_profile);
+  return icc_profile;
+}
+
+#if !defined(OS_WIN) && !defined(OS_MACOSX)
+// static
+ICCProfile ICCProfile::FromBestMonitor() {
+  return ICCProfile();
+}
+#endif
+
+// static
+ICCProfile ICCProfile::FromColorSpace(const gfx::ColorSpace& color_space) {
+  // Retrieve ICC profiles from the cache.
+  if (color_space.icc_profile_id_) {
+    Cache& cache = g_cache.Get();
+    base::AutoLock lock(cache.lock);
+
+    auto found = cache.id_to_icc_profile_mru.Get(color_space.icc_profile_id_);
+    if (found != cache.id_to_icc_profile_mru.end())
+      return found->second;
+  }
+  // TODO(ccameron): Support constructing ICC profiles from arbitrary ColorSpace
+  // objects.
+  return ICCProfile();
+}
+
+const std::vector<char>& ICCProfile::GetData() const {
+  return data_;
+}
+
+ColorSpace ICCProfile::GetColorSpace() const {
+  ColorSpace color_space;
+  color_space.valid_ = true;
+  color_space.icc_profile_id_ = id_;
+
+  // Move this ICC profile to the most recently used end of the cache.
+  {
+    Cache& cache = g_cache.Get();
+    base::AutoLock lock(cache.lock);
+
+    auto found = cache.id_to_icc_profile_mru.Get(id_);
+    if (found == cache.id_to_icc_profile_mru.end())
+      cache.id_to_icc_profile_mru.Put(id_, *this);
+  }
+  return color_space;
+}
+
+// static
+bool ICCProfile::IsValidProfileLength(size_t length) {
+  return length >= kMinProfileLength && length <= kMaxProfileLength;
+}
+
+}  // namespace gfx