1 files changed, 92 insertions, 0 deletions
diff --git a/mozglue/baseprofiler/core/BaseAndGeckoProfilerDetail.cpp b/mozglue/baseprofiler/core/BaseAndGeckoProfilerDetail.cpp
new file mode 100644
index 0000000000..213f25cf16
--- /dev/null
+++ b/mozglue/baseprofiler/core/BaseAndGeckoProfilerDetail.cpp
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/BaseAndGeckoProfilerDetail.h"
+
+#include <limits>
+#include <string_view>
+
+namespace mozilla::profiler::detail {
+
+constexpr std::string_view scPidPrefix = "pid:";
+
+// Convert a C string to a BaseProfilerProcessId. Return unspecified
+// BaseProfilerProcessId if the string is not exactly a valid pid.
+static baseprofiler::BaseProfilerProcessId StringToPid(const char* aString) {
+  if (!aString || aString[0] == '\0') {
+    // Null or empty.
+    return baseprofiler::BaseProfilerProcessId{};
+  }
+
+  if (aString[0] == '0') {
+    if (aString[1] != '\0') {
+      // Don't accept leading zeroes.
+      return baseprofiler::BaseProfilerProcessId{};
+    }
+    return baseprofiler::BaseProfilerProcessId::FromNumber(0);
+  }
+
+  using PidNumber = baseprofiler::BaseProfilerProcessId::NumberType;
+  PidNumber pid = 0;
+  for (;;) {
+    const char c = *aString;
+    if (c == '\0') {
+      break;
+    }
+    if (c < '0' || c > '9') {
+      // Only accept decimal digits.
+      return baseprofiler::BaseProfilerProcessId{};
+    }
+    static_assert(!std::numeric_limits<PidNumber>::is_signed,
+                  "The following relies on unsigned arithmetic");
+    PidNumber newPid = pid * 10u + PidNumber(c - '0');
+    if (newPid < pid) {
+      // Unsigned overflow.
+      return baseprofiler::BaseProfilerProcessId{};
+    }
+    pid = newPid;
+    ++aString;
+  }
+  return baseprofiler::BaseProfilerProcessId::FromNumber(pid);
+}
+
+[[nodiscard]] MFBT_API bool FilterHasPid(
+    const char* aFilter, baseprofiler::BaseProfilerProcessId aPid) {
+  if (strncmp(aFilter, scPidPrefix.data(), scPidPrefix.length()) != 0) {
+    // The filter is not starting with "pid:".
+    return false;
+  }
+
+  return StringToPid(aFilter + scPidPrefix.length()) == aPid;
+}
+
+[[nodiscard]] MFBT_API bool FiltersExcludePid(
+    Span<const char* const> aFilters,
+    baseprofiler::BaseProfilerProcessId aPid) {
+  if (aFilters.empty()) {
+    return false;
+  }
+
+  // First, check if the list only contains "pid:..." strings.
+  for (const char* const filter : aFilters) {
+    if (strncmp(filter, scPidPrefix.data(), scPidPrefix.length()) != 0) {
+      // At least one filter is *not* a "pid:...", our pid is not excluded.
+      return false;
+    }
+  }
+
+  // Here, all filters start with "pid:". Check if the given pid is included.
+  for (const char* const filter : aFilters) {
+    if (StringToPid(filter + scPidPrefix.length()) == aPid) {
+      // Our pid is present, so it's not excluded.
+      return false;
+    }
+  }
+  // Our pid was not in a list of only pids, so it's excluded.
+  return true;
+}
+
+}  // namespace mozilla::profiler::detail