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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/media/capture/sub_capture_target_id_web_contents_helper.h"
#include <string>
#include <string_view>
#include <vector>
#include "base/containers/contains.h"
#include "base/functional/callback.h"
#include "base/strings/string_number_conversions.h"
#include "base/token.h"
#include "base/uuid.h"
#include "build/build_config.h"
#include "content/browser/renderer_host/render_frame_host_impl.h"
#include "content/common/content_export.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/web_contents.h"
#if BUILDFLAG(IS_ANDROID)
#error Region Capture not supported on Android.
#endif
namespace content {
// TODO(crbug.com/40203554): Remove this protected static function.
// See header for more details.
base::Token SubCaptureTargetIdWebContentsHelper::GUIDToToken(
const base::Uuid& guid) {
std::string lowercase = guid.AsLowercaseString();
// |lowercase| is either empty, or follows the expected pattern.
// TODO(crbug.com/40201847): Resolve open question of correct treatment
// of an invalid GUID.
if (lowercase.empty()) {
return base::Token();
}
DCHECK_EQ(lowercase.length(), 32u + 4u); // 32 hex-chars; 4 hyphens.
base::RemoveChars(lowercase, "-", &lowercase);
DCHECK_EQ(lowercase.length(), 32u); // 32 hex-chars; 0 hyphens.
std::string_view string_piece(lowercase);
uint64_t high = 0;
bool success = base::HexStringToUInt64(string_piece.substr(0, 16), &high);
DCHECK(success);
uint64_t low = 0;
success = base::HexStringToUInt64(string_piece.substr(16, 16), &low);
DCHECK(success);
return base::Token(high, low);
}
WebContents* SubCaptureTargetIdWebContentsHelper::GetRelevantWebContents(
GlobalRenderFrameHostId rfh_id) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
// TODO(crbug.com/40287690): Remove this redundant check.
if (rfh_id == GlobalRenderFrameHostId()) {
return nullptr;
}
RenderFrameHostImpl* rfhi = RenderFrameHostImpl::FromID(rfh_id);
if (!rfhi || !rfhi->IsActive()) {
return nullptr;
}
rfhi = rfhi->GetMainFrame(); // TODO(crbug.com/40287690): Remove this line.
if (GetContentClient()
->browser()
->UseOutermostMainFrameOrEmbedderForSubCaptureTargets()) {
rfhi = rfhi->GetOutermostMainFrameOrEmbedder();
}
return WebContents::FromRenderFrameHost(rfhi);
}
SubCaptureTargetIdWebContentsHelper::SubCaptureTargetIdWebContentsHelper(
WebContents* web_contents)
: WebContentsObserver(web_contents),
WebContentsUserData<SubCaptureTargetIdWebContentsHelper>(*web_contents) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(web_contents);
}
SubCaptureTargetIdWebContentsHelper::~SubCaptureTargetIdWebContentsHelper() =
default;
std::string SubCaptureTargetIdWebContentsHelper::ProduceId(Type type) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
CHECK(type == Type::kCropTarget || type == Type::kRestrictionTarget);
std::vector<base::Token>& ids =
(type == Type::kCropTarget) ? crop_ids_ : restriction_ids_;
// Prevent Web-applications from producing an excessive number of IDs.
if (ids.size() >= kMaxIdsPerWebContents) {
return std::string();
}
// Given the exceedingly low likelihood of collisions, the check for
// uniqueness could have theoretically been skipped. But it's cheap
// enough to perform, given that `kMaxIdsPerWebContents` is so small
// compared to the space of GUIDs, and it guarantees we never silently fail
// the application by cropping/restricting to the wrong, duplicate target.
base::Uuid guid;
base::Token id;
do {
guid = base::Uuid::GenerateRandomV4();
id = GUIDToToken(guid);
} while (IsAssociatedWith(id, type));
ids.push_back(id);
return guid.AsLowercaseString();
}
bool SubCaptureTargetIdWebContentsHelper::IsAssociatedWith(
const base::Token& id,
Type type) const {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
CHECK(type == Type::kCropTarget || type == Type::kRestrictionTarget);
const std::vector<base::Token>& ids =
(type == Type::kCropTarget) ? crop_ids_ : restriction_ids_;
return base::Contains(ids, id);
}
void SubCaptureTargetIdWebContentsHelper::ReadyToCommitNavigation(
NavigationHandle* navigation_handle) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(navigation_handle);
// Cross-document navigation of the top-level frame invalidates all IDs
// associated with the observed WebContents.
// Using IsInPrimaryMainFrame is valid here since the browser only caches this
// state for the active main frame.
if (!navigation_handle->IsSameDocument() &&
navigation_handle->IsInPrimaryMainFrame()) {
ClearIds();
}
}
void SubCaptureTargetIdWebContentsHelper::ClearIds() {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
crop_ids_.clear();
restriction_ids_.clear();
}
WEB_CONTENTS_USER_DATA_KEY_IMPL(SubCaptureTargetIdWebContentsHelper);
} // namespace content
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