1 files changed, 109 insertions, 0 deletions
diff --git a/lldb/source/Interpreter/CommandHistory.cpp b/lldb/source/Interpreter/CommandHistory.cpp
new file mode 100644
index 0000000000000..0be61f836e002
--- /dev/null
+++ b/lldb/source/Interpreter/CommandHistory.cpp
@@ -0,0 +1,109 @@
+//===-- CommandHistory.cpp --------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <inttypes.h>
+
+#include "lldb/Interpreter/CommandHistory.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+CommandHistory::CommandHistory() : m_mutex(), m_history() {}
+
+CommandHistory::~CommandHistory() {}
+
+size_t CommandHistory::GetSize() const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  return m_history.size();
+}
+
+bool CommandHistory::IsEmpty() const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  return m_history.empty();
+}
+
+llvm::Optional<llvm::StringRef>
+CommandHistory::FindString(llvm::StringRef input_str) const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  if (input_str.size() < 2)
+    return llvm::None;
+
+  if (input_str[0] != g_repeat_char)
+    return llvm::None;
+
+  if (input_str[1] == g_repeat_char) {
+    if (m_history.empty())
+      return llvm::None;
+    return llvm::StringRef(m_history.back());
+  }
+
+  input_str = input_str.drop_front();
+
+  size_t idx = 0;
+  if (input_str.front() == '-') {
+    if (input_str.drop_front(1).getAsInteger(0, idx))
+      return llvm::None;
+    if (idx >= m_history.size())
+      return llvm::None;
+    idx = m_history.size() - idx;
+  } else {
+    if (input_str.getAsInteger(0, idx))
+      return llvm::None;
+    if (idx >= m_history.size())
+      return llvm::None;
+  }
+
+  return llvm::StringRef(m_history[idx]);
+}
+
+llvm::StringRef CommandHistory::GetStringAtIndex(size_t idx) const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  if (idx < m_history.size())
+    return m_history[idx];
+  return "";
+}
+
+llvm::StringRef CommandHistory::operator[](size_t idx) const {
+  return GetStringAtIndex(idx);
+}
+
+llvm::StringRef CommandHistory::GetRecentmostString() const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  if (m_history.empty())
+    return "";
+  return m_history.back();
+}
+
+void CommandHistory::AppendString(llvm::StringRef str, bool reject_if_dupe) {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  if (reject_if_dupe) {
+    if (!m_history.empty()) {
+      if (str == m_history.back())
+        return;
+    }
+  }
+  m_history.push_back(str);
+}
+
+void CommandHistory::Clear() {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  m_history.clear();
+}
+
+void CommandHistory::Dump(Stream &stream, size_t start_idx,
+                          size_t stop_idx) const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
+  stop_idx = std::min(stop_idx + 1, m_history.size());
+  for (size_t counter = start_idx; counter < stop_idx; counter++) {
+    const std::string hist_item = m_history[counter];
+    if (!hist_item.empty()) {
+      stream.Indent();
+      stream.Printf("%4" PRIu64 ": %s\n", (uint64_t)counter, hist_item.c_str());
+    }
+  }
+}