1 files changed, 122 insertions, 0 deletions
diff --git a/third_party/libwebrtc/test/scoped_key_value_config.cc b/third_party/libwebrtc/test/scoped_key_value_config.cc
new file mode 100644
index 0000000000..df84462637
--- /dev/null
+++ b/third_party/libwebrtc/test/scoped_key_value_config.cc
@@ -0,0 +1,122 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "test/scoped_key_value_config.h"
+
+#include "rtc_base/checks.h"
+#include "system_wrappers/include/field_trial.h"
+#include "test/field_trial.h"
+
+namespace {
+
+// This part is copied from system_wrappers/field_trial.cc.
+void InsertIntoMap(
+    std::map<std::string, std::string, std::less<>>& key_value_map,
+    absl::string_view s) {
+  std::string::size_type field_start = 0;
+  while (field_start < s.size()) {
+    std::string::size_type separator_pos = s.find('/', field_start);
+    RTC_CHECK_NE(separator_pos, std::string::npos)
+        << "Missing separator '/' after field trial key.";
+    RTC_CHECK_GT(separator_pos, field_start)
+        << "Field trial key cannot be empty.";
+    std::string key(s.substr(field_start, separator_pos - field_start));
+    field_start = separator_pos + 1;
+
+    RTC_CHECK_LT(field_start, s.size())
+        << "Missing value after field trial key. String ended.";
+    separator_pos = s.find('/', field_start);
+    RTC_CHECK_NE(separator_pos, std::string::npos)
+        << "Missing terminating '/' in field trial string.";
+    RTC_CHECK_GT(separator_pos, field_start)
+        << "Field trial value cannot be empty.";
+    std::string value(s.substr(field_start, separator_pos - field_start));
+    field_start = separator_pos + 1;
+
+    key_value_map[key] = value;
+  }
+  // This check is technically redundant due to earlier checks.
+  // We nevertheless keep the check to make it clear that the entire
+  // string has been processed, and without indexing past the end.
+  RTC_CHECK_EQ(field_start, s.size());
+}
+
+}  // namespace
+
+namespace webrtc {
+namespace test {
+
+ScopedKeyValueConfig::ScopedKeyValueConfig()
+    : ScopedKeyValueConfig(nullptr, "") {}
+
+ScopedKeyValueConfig::ScopedKeyValueConfig(absl::string_view s)
+    : ScopedKeyValueConfig(nullptr, s) {}
+
+ScopedKeyValueConfig::ScopedKeyValueConfig(ScopedKeyValueConfig& parent,
+                                           absl::string_view s)
+    : ScopedKeyValueConfig(&parent, s) {}
+
+ScopedKeyValueConfig::ScopedKeyValueConfig(ScopedKeyValueConfig* parent,
+                                           absl::string_view s)
+    : parent_(parent), leaf_(nullptr) {
+  InsertIntoMap(key_value_map_, s);
+
+  if (!s.empty()) {
+    // Also store field trials in global string (until we get rid of it).
+    scoped_field_trials_ = std::make_unique<ScopedFieldTrials>(s);
+  }
+
+  if (parent == nullptr) {
+    // We are root, set leaf_.
+    leaf_ = this;
+  } else {
+    // Link root to new leaf.
+    GetRoot(parent)->leaf_ = this;
+    RTC_DCHECK(leaf_ == nullptr);
+  }
+}
+
+ScopedKeyValueConfig::~ScopedKeyValueConfig() {
+  if (parent_) {
+    GetRoot(parent_)->leaf_ = parent_;
+  }
+}
+
+ScopedKeyValueConfig* ScopedKeyValueConfig::GetRoot(ScopedKeyValueConfig* n) {
+  while (n->parent_ != nullptr) {
+    n = n->parent_;
+  }
+  return n;
+}
+
+std::string ScopedKeyValueConfig::GetValue(absl::string_view key) const {
+  if (parent_ == nullptr) {
+    return leaf_->LookupRecurse(key);
+  } else {
+    return LookupRecurse(key);
+  }
+}
+
+std::string ScopedKeyValueConfig::LookupRecurse(absl::string_view key) const {
+  auto it = key_value_map_.find(key);
+  if (it != key_value_map_.end())
+    return it->second;
+
+  if (parent_) {
+    return parent_->LookupRecurse(key);
+  }
+
+  // When at the root, check the global string so that test programs using
+  // a mix between ScopedKeyValueConfig and the global string continue to work
+  return webrtc::field_trial::FindFullName(std::string(key));
+}
+
+}  // namespace test
+}  // namespace webrtc