Add MinidumpThreadListWriter::InitializeFromSnapshot()

minidump/minidump_thread_id_map.h

Index: minidump/minidump_thread_id_map.h
diff --git a/minidump/minidump_thread_id_map.h b/minidump/minidump_thread_id_map.h
new file mode 100644
index 0000000000000000000000000000000000000000..33b105fba19c298ed7a0e0d97138f8010bdac1ba
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+++ b/minidump/minidump_thread_id_map.h
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+// Copyright 2014 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.
+
+#ifndef CRASHPAD_MINIDUMP_MINIDUMP_THREAD_ID_MAP_H_
+#define CRASHPAD_MINIDUMP_MINIDUMP_THREAD_ID_MAP_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <vector>
+
+namespace crashpad {
+
+class ThreadSnapshot;
+
+//! \brief A map that connects 64-bit snapshot thread IDs to 32-bit minidump
+//!     thread IDs.
+//!
+//! 64-bit snapshot thread IDs are obtained from ThreadSnapshot::ThreadID().
+//! 32-bit minidump thread IDs are stored in MINIDUMP_THREAD::ThreadId.
+//!
+//! A ThreadIDMap ensures that there are no collisions among the set of 32-bit
+//! minidump thread IDs.
+using MinidumpThreadIDMap = std::map<uint64_t, uint32_t>;
+
+//! \brief Builds a MinidumpThreadIDMap for a group of ThreadSnapshot objects.
+//!
+//! \param[in] thread_snapshots The thread snapshots to use as source data.
+//! \param[out] thread_id_map A MinidumpThreadIDMap to be built by this method.
+//!     This map must be empty when this function is called.
+//!
+//! The map ensures that for any unique 64-bit thread ID found in a
+//! ThreadSnapshot, the 32-bit thread ID used in a minidump file will also be
+//! unique.
+void BuildMinidumpThreadIDMap(
+    const std::vector<const ThreadSnapshot*>& thread_snapshots,
+    MinidumpThreadIDMap* thread_id_map);
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_MINIDUMP_MINIDUMP_THREAD_ID_MAP_H_