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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chromeos/ash/components/kcer/token_key_finder.h"
#include <optional>
#include "base/containers/contains.h"
#include "base/containers/flat_map.h"
#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_refptr.h"
#include "base/types/expected.h"
#include "chromeos/ash/components/kcer/kcer.h"
namespace kcer::internal {
// static
scoped_refptr<TokenKeyFinder> TokenKeyFinder::Create(
int results_to_receive,
base::OnceCallback<void(base::expected<std::optional<Token>, Error>)>
callback) {
return base::MakeRefCounted<TokenKeyFinder>(
base::PassKey<TokenKeyFinder>(), results_to_receive, std::move(callback));
}
TokenKeyFinder::TokenKeyFinder(
base::PassKey<TokenKeyFinder>,
int results_to_receive,
base::OnceCallback<void(base::expected<std::optional<Token>, Error>)>
callback)
: callbacks_to_create_(results_to_receive),
results_to_receive_(results_to_receive),
callback_(std::move(callback)) {
CHECK_GT(results_to_receive_, 0);
}
TokenKeyFinder::~TokenKeyFinder() {
// If `callbacks_to_create_` is positive, then not enough callbacks were
// created and the result was never returned. If negative, then the result
// was returned before receiving all sub-results.
CHECK_EQ(callbacks_to_create_, 0);
}
base::OnceCallback<void(base::expected<bool, Error>)>
TokenKeyFinder::GetCallback(Token token) {
this->callbacks_to_create_--;
CHECK_GE(this->callbacks_to_create_, 0);
return base::BindOnce(&TokenKeyFinder::HandleOneResult,
base::RetainedRef(this), token);
}
void TokenKeyFinder::HandleOneResult(Token token,
base::expected<bool, Error> result) {
if (!callback_) {
// The key was already found earlier, ignore this result.
return;
}
if (result.has_value() && (result.value() == true)) {
return std::move(callback_).Run(token);
}
if (!result.has_value()) {
CHECK(!base::Contains(errors_, token));
errors_[token] = result.error();
}
if (--results_to_receive_ > 0) {
// Key not found so far, but more results will come. Wait for them.
return;
}
// else: All results were received, the key was not found.
if (!errors_.empty()) {
// Multiple different errors could be present, return just one of them for
// simplicity.
return std::move(callback_).Run(base::unexpected(errors_.begin()->second));
}
return std::move(callback_).Run(/*token=*/std::nullopt);
}
} // namespace kcer::internal
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