[lldb] Add fzf_history command to examples

lldb/examples/python/fzf_history.py

@@ -0,0 +1,110 @@
+import os
+import re
+import sys
+import subprocess
+import tempfile
+
+import lldb
+
+
+@lldb.command()
+def fzf_history(debugger, cmdstr, ctx, result, _):
+    """Use fzf to search and select from lldb command history."""
+    history_file = os.path.expanduser("~/.lldb/lldb-widehistory")
+    if not os.path.exists(history_file):
+        result.SetError("history file does not exist")
+        return
+    history = _load_history(history_file)
+
+    if sys.platform != "darwin":
+        # The ability to integrate fzf's result into lldb uses copy and paste.
+        # In absense of copy and paste, run the selected command directly.
+        temp_file = tempfile.NamedTemporaryFile("r")
+        fzf_command = (
+            "fzf",
+            "--no-sort",
+            f"--query={cmdstr}",
+            f"--bind=enter:execute-silent(echo -n {{}} > {temp_file.name})+accept",
+        )
+        subprocess.run(fzf_command, input=history, text=True)
+        command = temp_file.read()
+        debugger.HandleCommand(command)
+        return
+
+    # Capture the current pasteboard contents to restore after overwriting.
+    paste_snapshot = subprocess.run("pbpaste", text=True, capture_output=True).stdout
+
+    # On enter, copy the selected history entry into the pasteboard.
+    fzf_command = (
+        "fzf",
+        "--no-sort",
+        f"--query={cmdstr}",
+        "--bind=enter:execute-silent(echo -n {} | pbcopy)+close",
+    )
+    completed = subprocess.run(fzf_command, input=history, text=True)
+    # 130 is used for CTRL-C or ESC.
+    if completed.returncode not in (0, 130):
+        result.SetError("fzf failed")
+        return
+
+    # Get the user's selected history entry.
+    selected_command = subprocess.run("pbpaste", text=True, capture_output=True).stdout
+    if selected_command == paste_snapshot:
+        # Nothing was selected, no cleanup needed.
+        return
+
+    _handle_command(debugger, selected_command)
+
+    # Restore the pasteboard's contents.
+    subprocess.run("pbcopy", input=paste_snapshot, text=True)
+
+
+def _handle_command(debugger, command):
+    """Try pasting the command, and failing that, run it directly."""
+    if not command:
+        return
+
+    # Use applescript to paste the selected result into lldb's console.
+    paste_command = (
+        "osascript",
+        "-e",
+        'tell application "System Events" to keystroke "v" using command down',
+    )
+    completed = subprocess.run(paste_command, capture_output=True)
+
+    if completed.returncode != 0:
+        # The above applescript requires the "control your computer" permission.
+        #     Settings > Private & Security > Accessibility
+        # If not enabled, fallback to running the command.
+        debugger.HandleCommand(command)
+
+
+def _load_history(history_file):
+    """Load, decode, parse, and prepare an lldb history file for fzf."""
+    with open(history_file) as f:
+        history_contents = f.read()
+
+    history_decoded = re.sub(r"\\0([0-7][0-7])", _decode_char, history_contents)
+    history_lines = history_decoded.splitlines()
+
+    # Skip the header line (_HiStOrY_V2_)
+    del history_lines[0]
+    # Reverse to show latest first.
+    history_lines.reverse()
+
+    history_commands = []
+    history_seen = set()
+    for line in history_lines:
+        line = line.strip()
+        # Skip empty lines, single character commands, and duplicates.
+        if line and len(line) > 1 and line not in history_seen:
+            history_commands.append(line)
+            history_seen.add(line)
+
+    return "\n".join(history_commands)
+
+
+def _decode_char(match):
+    """Decode octal strings ('\0NN') into a single character string."""
+    code = int(match.group(1), base=8)
+    return chr(code)