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[lldb] Take a sledgehammer approach to resizing the statusline #146578

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Merged
merged 3 commits into from
Jul 3, 2025
Merged

[lldb] Take a sledgehammer approach to resizing the statusline #146578

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a0ebe1e
[lldb] Take a sledgehammer approach to resizing the statusline
JDevlieghere Jul 1, 2025
46fe057
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JDevlieghere Jul 1, 2025
448dc22
Add FIXME
JDevlieghere Jul 3, 2025
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4 changes: 1 addition & 3 deletions lldb/include/lldb/Core/Statusline.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,12 +36,10 @@ class Statusline {
/// Draw the statusline with the given text.
void Draw(std::string msg);

/// Update terminal dimensions.
void UpdateTerminalProperties();

enum ScrollWindowMode {
EnableStatusline,
DisableStatusline,
ResizeStatusline,
};

/// Set the scroll window for the given mode.
Expand Down
46 changes: 25 additions & 21 deletions lldb/source/Core/Statusline.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#define ANSI_SAVE_CURSOR ESCAPE "7"
#define ANSI_RESTORE_CURSOR ESCAPE "8"
#define ANSI_CLEAR_BELOW ESCAPE "[J"
#define ANSI_CLEAR_SCREEN ESCAPE "[2J"
#define ANSI_SET_SCROLL_ROWS ESCAPE "[1;%ur"
#define ANSI_TO_START_OF_ROW ESCAPE "[%u;1f"
#define ANSI_REVERSE_VIDEO ESCAPE "[7m"
Expand All @@ -41,10 +42,12 @@ Statusline::Statusline(Debugger &debugger)
Statusline::~Statusline() { Disable(); }

void Statusline::TerminalSizeChanged() {
UpdateTerminalProperties();
m_terminal_width = m_debugger.GetTerminalWidth();
m_terminal_height = m_debugger.GetTerminalHeight();

// This definitely isn't signal safe, but the best we can do, until we
// have proper signal-catching thread.
UpdateScrollWindow(ResizeStatusline);

// Draw the old statusline.
Redraw(/*update=*/false);
}

Expand Down Expand Up @@ -85,38 +88,39 @@ void Statusline::Draw(std::string str) {
locked_stream << ANSI_RESTORE_CURSOR;
}

void Statusline::UpdateTerminalProperties() {
UpdateScrollWindow(DisableStatusline);
m_terminal_width = m_debugger.GetTerminalWidth();
m_terminal_height = m_debugger.GetTerminalHeight();
UpdateScrollWindow(EnableStatusline);
}

void Statusline::UpdateScrollWindow(ScrollWindowMode mode) {
assert(m_terminal_width != 0 && m_terminal_height != 0);

lldb::LockableStreamFileSP stream_sp = m_debugger.GetOutputStreamSP();
if (!stream_sp)
return;

const unsigned scroll_height =
(mode == DisableStatusline) ? m_terminal_height : m_terminal_height - 1;

const unsigned reduced_scroll_window = m_terminal_height - 1;
LockedStreamFile locked_stream = stream_sp->Lock();

if (mode == EnableStatusline) {
switch (mode) {
case EnableStatusline:
// Move everything on the screen up.
locked_stream << '\n';
locked_stream.Printf(ANSI_UP_ROWS, 1);
}

locked_stream << ANSI_SAVE_CURSOR;
locked_stream.Printf(ANSI_SET_SCROLL_ROWS, scroll_height);
locked_stream << ANSI_RESTORE_CURSOR;

if (mode == DisableStatusline) {
// Reduce the scroll window.
locked_stream << ANSI_SAVE_CURSOR;
locked_stream.Printf(ANSI_SET_SCROLL_ROWS, reduced_scroll_window);
locked_stream << ANSI_RESTORE_CURSOR;
break;
case DisableStatusline:
// Reset the scroll window.
locked_stream << ANSI_SAVE_CURSOR;
locked_stream.Printf(ANSI_SET_SCROLL_ROWS, 0);
locked_stream << ANSI_RESTORE_CURSOR;
// Clear the screen below to hide the old statusline.
locked_stream << ANSI_CLEAR_BELOW;
break;
case ResizeStatusline:
// Clear the screen and update the scroll window.
locked_stream << ANSI_CLEAR_SCREEN;
locked_stream.Printf(ANSI_SET_SCROLL_ROWS, reduced_scroll_window);
break;
}

m_debugger.RefreshIOHandler();
Expand Down
10 changes: 4 additions & 6 deletions lldb/test/API/functionalities/statusline/TestStatusline.py
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Expand Up @@ -67,9 +67,7 @@ def test(self):
self.expect('set set separator "| "')

# Hide the statusline and check or the control character.
self.expect(
"set set show-statusline false", ["\x1b[1;{}r".format(self.TERMINAL_HEIGHT)]
)
self.expect("set set show-statusline false", ["\x1b[1;0r"])

def test_no_color(self):
"""Basic test for the statusline with colors disabled."""
Expand Down Expand Up @@ -114,6 +112,6 @@ def test_resize(self):
self.resize()
self.expect("set set show-statusline true", ["no target"])
self.resize(20, 60)
# Check for the escape code to resize the scroll window, followed by
# the prompt.
self.child.expect(re.escape("\x1b[1;19r\x1b8(lldb)"))
# Check for the escape code to resize the scroll window.
self.child.expect(re.escape("\x1b[1;19r"))
self.child.expect("(lldb)")
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