Locate test data more robustly

util/test/paths.cc

Index: util/test/paths.cc
diff --git a/util/test/paths.cc b/util/test/paths.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5634b62dd10696dd7c0a1e1ed4ef5f1d25208076
--- /dev/null
+++ b/util/test/paths.cc
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+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/test/paths.h"
+
+#include <stdlib.h>
+#include <sys/stat.h>
+
+#include "base/logging.h"
+#include "build/build_config.h"
+
+namespace crashpad {
+namespace test {
+
+namespace {
+
+bool IsTestDataRoot(const base::FilePath& candidate) {
+  const base::FilePath marker_path =
+      candidate.Append(FILE_PATH_LITERAL("util"))
+          .Append(FILE_PATH_LITERAL("test"))
+          .Append(FILE_PATH_LITERAL("paths_test_data_root.txt"));
+
+#if !defined(OS_WIN)
+  struct stat stat_buf;
+  int rv = stat(marker_path.value().c_str(), &stat_buf);
+#else
+  struct _stat stat_buf;
+  int rv = _wstat(marker_path.value().c_str(), &stat_buf);
+#endif
+
+  return rv == 0;
+}
+
+base::FilePath TestDataRootInternal() {
+#if !defined(OS_WIN)
+  const char* environment_value = getenv("CRASHPAD_TEST_DATA_ROOT");
+#else  // defined(OS_WIN)
+  const wchar_t* environment_value = _wgetenv(L"CRASHPAD_TEST_DATA_ROOT");
+#endif
+
+  if (environment_value) {
+    // It was specified explicitly, so use it even if it seems incorrect.
+    if (!IsTestDataRoot(base::FilePath(environment_value))) {
+      LOG(WARNING) << "CRASHPAD_TEST_DATA_ROOT seems invalid, honoring anyway";
+    }
+
+    return base::FilePath(environment_value);
+  }
+
+  // In a standalone build, the test executable is usually at
+  // out/{Debug,Release} relative to the Crashpad root.
+  const base::FilePath executable = Paths::Executable();
+  base::FilePath candidate =
+      base::FilePath(executable.DirName()
+                         .Append(base::FilePath::kParentDirectory)
+                         .Append(base::FilePath::kParentDirectory));
+  if (IsTestDataRoot(candidate)) {
+    return candidate;
+  }
+
+  // In an in-Chromium build, the test executable is usually at
+  // out/{Debug,Release} relative to the Chromium root, and the Crashpad root is
+  // at third_party/crashpad/crashpad relative to the Chromium root.
+  candidate = candidate.Append(FILE_PATH_LITERAL("third_party"))
+                  .Append(FILE_PATH_LITERAL("crashpad"))
+                  .Append(FILE_PATH_LITERAL("crashpad"));
+  if (IsTestDataRoot(candidate)) {
+    return candidate;
+  }
+
+  // If nothing else worked, use the current directory, issuing a warning if it
+  // doesn’t seem right.
+  if (!IsTestDataRoot(base::FilePath(base::FilePath::kCurrentDirectory))) {
+    LOG(WARNING) << "could not locate a valid test data root";
+  }
+
+  return base::FilePath(base::FilePath::kCurrentDirectory);
+}
+
+}  // namespace
+
+// static
+base::FilePath Paths::TestDataRoot() {
+  static base::FilePath* test_data_root =
+      new base::FilePath(TestDataRootInternal());
+  return *test_data_root;
+}
+
+}  // namespace test
+}  // namespace crashpad