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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <tuple>
#include "base/containers/span.h"
#include "third_party/do_not_rewrite/third_party_api.h"
int UnsafeIndex(); // Return out-of-bounds index.
bool Bool(); // Unknown boolean value.
// Expected rewrite:
// base::span<int> GetFirstPartyBuffer() {
base::span<int> GetFirstPartyBuffer() {
return new int[10];
}
void test_cycle_isolated() {
// An isolated cycle with no dependencies.
//
// As of today, it gets rewritten, because nothing prevents it from being
// rewritten, and some of its dependents would like to be spanified.
// Expected rewrite:
// base::span<int> cycle_1;
base::span<int> cycle_1;
// Expected rewrite:
// base::span<int> cycle_2;
base::span<int> cycle_2;
cycle_1 = cycle_2;
cycle_2 = cycle_1;
// Expected rewrite:
// base::span<int> output;
base::span<int> output;
if (Bool()) {
output = GetFirstPartyBuffer();
} else {
output = cycle_1;
}
std::ignore = output[UnsafeIndex()];
}
void test_cycle_depending_on_first_party_buffer() {
// A cycle that can be rewritten, because it depends on something that can be
// rewritten, and dependants would like to be spanified.
// Expected rewrite:
// base::span<int> cycle_1 = GetFirstPartyBuffer();
base::span<int> cycle_1 = GetFirstPartyBuffer();
// Expected rewrite:
// base::span<int> cycle_2;
base::span<int> cycle_2;
cycle_1 = cycle_2;
cycle_2 = cycle_1;
// Expected rewrite:
// base::span<int> output;
base::span<int> output;
if (Bool()) {
output = GetFirstPartyBuffer();
} else {
output = cycle_1;
}
std::ignore = output[UnsafeIndex()];
}
void test_cycle_depending_on_third_party_buffer() {
// A cycle that can't be rewritten, because it depends on something that can't
// be rewritten.
// The current implementation of the spanifier tool assumes that all third-
// party functions tell the size someway. The implementation is below.
// https://source.chromium.org/chromium/chromium/src/+/main:tools/clang/spanify/Spanifier.cpp;drc=f240549b481969cf1442aac67a9086bfd639787c;l=2190-2191
//
// This test case was originally introduced to test that a buffer returned by
// a third-party function shouldn't be rewritten to base::span, but it's not
// been the intended behavior. A bug caused that the buffer doesn't get
// rewritten, but the bug was fixed in https://crrev.com/c/6348037.
//
// TODO: Revisit this point and determine whether buffers returned by third-
// party functions must be spanified unconditionally or in a certain
// condition.
//
// Expected rewrite:
// base::span<int> cycle_1 = GetThirdPartyBuffer();
base::span<int> cycle_1 = GetThirdPartyBuffer();
// Expected rewrite:
// base::span<int> cycle_2;
base::span<int> cycle_2;
cycle_1 = cycle_2;
cycle_2 = cycle_1;
// Expected rewrite:
// base::span<int> output;
base::span<int> output;
if (Bool()) {
output = GetFirstPartyBuffer();
} else {
output = cycle_1;
}
std::ignore = output[UnsafeIndex()];
}
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