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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/base/cocoa/permissions_utils.h"
#include <CoreGraphics/CoreGraphics.h>
#include <Foundation/Foundation.h>
#import <ScreenCaptureKit/ScreenCaptureKit.h>
#include "base/apple/bridging.h"
#include "base/apple/foundation_util.h"
#include "base/apple/scoped_cftyperef.h"
#include "base/feature_list.h"
#include "base/logging.h"
#include "base/mac/mac_util.h"
#include "base/task/thread_pool.h"
namespace ui {
namespace {
BASE_FEATURE(kWarmScreenCaptureSonoma,
"WarmScreenCaptureSonoma",
base::FEATURE_ENABLED_BY_DEFAULT);
BASE_FEATURE(kWarmScreenCaptureSequoia,
"WarmScreenCaptureSequoia",
base::FEATURE_DISABLED_BY_DEFAULT);
bool ShouldWarmScreenCapture() {
const int macos_version = base::mac::MacOSVersion();
// On macOS < 14, we're using CGWindowListCreateImage to capture a screenshot.
// Starting in macOS 14, CGWindowListCreateImage causes a "your screen is
// being captured" chip to show in the menu bar while an app is capturing the
// screen, and if it's a one-time image capture, it shows for ten seconds.
if (macos_version < 14'00'00) {
return true;
}
// Kill switch, Sonoma.
if (macos_version < 15'00'00 &&
!base::FeatureList::IsEnabled(kWarmScreenCaptureSonoma)) {
return false;
}
// Feature disabled by default for Sequoia unless explicitly enabled.
if (macos_version >= 15'00'00 &&
!base::FeatureList::IsEnabled(kWarmScreenCaptureSequoia)) {
return false;
}
// On macOS >= 14, Apple introduced SCScreenshotManager that can be used to
// capture a screenshot without any notification shown to the user. There's a
// bug in this API that was fixed in 14.4.
if (macos_version >= 14'04'00) {
return true;
}
// macOS 14-14.3.
return false;
}
// Capture a screenshot and throw away the result.
void CaptureScreenshot() {
if (@available(macOS 14.0, *)) {
CHECK(base::FeatureList::IsEnabled(kWarmScreenCaptureSonoma));
// Capturing a screenshot using SCK involves three asynchronous steps:
// 1. Request shareable contents (getShareableContent...),
// 2. Instruct SCScreenshotManager to take a screenshot (captureImage...),
// 3. Receive a callback with the actual image.
auto shareable_content_handler = ^(SCShareableContent* content,
NSError* error) {
if (!content.displays.count || error) {
LOG(WARNING)
<< "Failed to get shareable content during WarmScreenCapture.";
return;
}
SCDisplay* first_display = content.displays.firstObject;
SCStreamConfiguration* config = [[SCStreamConfiguration alloc] init];
// Set the size to something small to make it clear to anyone reading the
// code that the screenshot contains no real information.
config.width = 16;
config.height = 10;
auto screenshot_handler = ^(CGImageRef sampleBuffer, NSError* sc_error) {
// Do nothing.
};
SCContentFilter* filter =
[[SCContentFilter alloc] initWithDisplay:first_display
excludingWindows:@[]];
[SCScreenshotManager captureImageWithFilter:filter
configuration:config
completionHandler:screenshot_handler];
};
[SCShareableContent
getShareableContentExcludingDesktopWindows:true
onScreenWindowsOnly:true
completionHandler:shareable_content_handler];
} else {
base::apple::ScopedCFTypeRef<CGImageRef>(
CGWindowListCreateImage(CGRectInfinite, kCGWindowListOptionOnScreenOnly,
kCGNullWindowID, kCGWindowImageDefault));
}
}
} // namespace
bool IsScreenCaptureAllowed() {
return CGPreflightScreenCaptureAccess();
}
bool TryPromptUserForScreenCapture() {
return CGRequestScreenCaptureAccess();
}
void WarmScreenCapture() {
if (!ShouldWarmScreenCapture()) {
return;
}
// WarmScreenCapture() is meant to be called during early startup. Since the
// calls to warm the cache may block, execute them off the main thread so we
// don't hold up startup. To be effective these calls need to run before
// Chrome is updated. Running them off the main thread technically opens us
// to a race condition, however updating happens way later so this is not a
// concern.
base::ThreadPool::PostTask(
FROM_HERE,
// Checking screen capture access hits the TCC.db and reads Chrome's
// code signature from disk, marking as MayBlock.
{base::MayBlock(), base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
base::BindOnce([] {
if (IsScreenCaptureAllowed()) {
CaptureScreenshot();
}
}));
}
} // namespace ui
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