[FarGroup/FarManager] master: More robust palette reading (01755e643)

[farg...@farmanager.com]

Repository : https://github.com/FarGroup/FarManager
On branch : master
Link : https://github.com/FarGroup/FarManager/commit/01755e6434423c3179223986200387b23872de71

>---------------------------------------------------------------

commit 01755e6434423c3179223986200387b23872de71
Author: Alex Alabuzhev <alab...@gmail.com>
Date: Thu Feb 19 21:14:09 2026 +0000

More robust palette reading


>---------------------------------------------------------------

01755e6434423c3179223986200387b23872de71
far/changelog | 5 +++++
far/console.cpp | 68 ++++++++++++++++++++++++++++++++++++++++++++-------------
far/vbuild.m4 | 2 +-
3 files changed, 59 insertions(+), 16 deletions(-)

diff --git a/far/changelog b/far/changelog
index 9d6e028b4..9f4e07329 100644
--- a/far/changelog
+++ b/far/changelog
@@ -1,3 +1,8 @@
+--------------------------------------------------------------------------------
+drkns 2026-02-19 21:12:02+00:00 - build 6645
+
+1. More robust palette reading.
+
--------------------------------------------------------------------------------
drkns 2026-02-10 02:33:01+00:00 - build 6644

diff --git a/far/console.cpp b/far/console.cpp
index 925f8c876..8afd70a2e 100644
--- a/far/console.cpp
+++ b/far/console.cpp
@@ -2148,24 +2148,26 @@ protected:
return true;
}

- static bool GetPaletteVT(std::array<COLORREF, 256>& Palette)
+ static size_t GetPaletteVT_partial(std::array<COLORREF, 256>& Palette, size_t const Offset, size_t const Count)
{
try
{
- LOGDEBUG(L"Reading VT palette - here be dragons"sv);
-
const auto
OSCPrefix = ESC L"]4"sv,
OSCSuffix = ST L""sv;

+ const auto Begin = static_cast<int>(Offset), End = static_cast<int>(Offset + Count);
+ const auto Under100 = std::max(0, 100 - Begin) - std::max(0, 100 - End);
+ const auto Under10 = std::max(0, 10 - Begin) - std::max(0, 10 - End);
+
string Request;
- Request.reserve(OSCPrefix.size() + L";255;?"sv.size() * Palette.size() - 100 - 10 + OSCSuffix.size());
+ Request.reserve(OSCPrefix.size() + L";255;?"sv.size() * Count - Under100 - Under10 + OSCSuffix.size());

// A single OSC for the whole thing.
// Querying the palette was introduced after the terse syntax, so it's fine.
Request = OSCPrefix;

- for (const auto i: std::views::iota(0uz, Palette.size()))
+ for (const auto i: std::views::iota(Offset, Offset + Count))
far::format_to(Request, L";{};?"sv, vt_color_index(static_cast<uint8_t>(i)));

Request += OSCSuffix;
@@ -2174,7 +2176,7 @@ protected:
if (ResponseData.empty())
{
LOGWARNING(L"OSC 4 query is not supported"sv, Request);
- return false;
+ return 0;
}

const auto make_exception = [&](source_location const& Location = source_location::current())
@@ -2216,7 +2218,11 @@ protected:
if (VtIndex >= Palette.size())
throw make_exception();

- auto& PaletteColor = Palette[vt_color_index(VtIndex)];
+ const auto NtIndex = vt_color_index(VtIndex);
+ if (NtIndex != Offset + ColorsSet)
+ throw make_exception();
+
+ auto& PaletteColor = Palette[NtIndex];

auto ColorStr = *SubIterator;
if (!ColorStr.starts_with(RGBPrefix))
@@ -2227,9 +2233,9 @@ protected:
if (ColorStr.size() != L"0000"sv.size() * 3 + 2)
throw make_exception();

- const auto color = [&](size_t const Offset)
+ const auto color = [&](size_t const RGBOffset)
{
- const auto Value = from_string<unsigned>(ColorStr.substr(Offset * L"0000/"sv.size(), 4), {}, 16);
+ const auto Value = from_string<unsigned>(ColorStr.substr(RGBOffset * L"0000/"sv.size(), 4), {}, 16);
if (Value > 0xffff)
throw make_exception();

@@ -2240,19 +2246,51 @@ protected:
++ColorsSet;
}

- if (ColorsSet != Palette.size())
- throw make_exception();
-
- LOGDEBUG(L"VT palette read successfuly"sv);
- return true;
+ return ColorsSet;
}
catch (std::exception const& e)
{
LOGERROR(L"{}"sv, e);
- return false;
+ return 0;
}
}

+ static bool GetPaletteVT(std::array<COLORREF, 256>& Palette)
+ {
+ LOGDEBUG(L"Reading VT palette - here be dragons"sv);
+
+ static auto BatchSize = Palette.size();
+ static bool BatchSizeAdjusted = false;
+
+ for (size_t Offset = 0; Offset < Palette.size();)
+ {
+ const auto ColorsSet = GetPaletteVT_partial(Palette, Offset, std::min(BatchSize, Palette.size() - Offset));
+ if (ColorsSet == 0)
+ return false;
+
+ if (ColorsSet == Palette.size())
+ break; // Full palette read successfully, no need to continue
+
+ // Some terminals (e.g. wezterm/wezterm#6124) fail to return the whole response in one go,
+ // so we do multiple queries with increasing offsets.
+ // This is silly, but better than nothing.
+ LOGDEBUG(L"VT palette [{} - {}] read"sv, Offset, Offset + ColorsSet - 1);
+
+ // Skip already read
+ Offset += ColorsSet;
+
+ // No point in trying to read more than it can return
+ if (!BatchSizeAdjusted)
+ {
+ BatchSize = ColorsSet;
+ BatchSizeAdjusted = true;
+ }
+ }
+
+ LOGDEBUG(L"VT palette read successfuly"sv);
+ return true;
+ }
+
static bool GetPaletteNT(std::array<COLORREF, 256>& Palette)
{
if (!imports.GetConsoleScreenBufferInfoEx)
diff --git a/far/vbuild.m4 b/far/vbuild.m4
index c458223ef..77a875b3a 100644
--- a/far/vbuild.m4
+++ b/far/vbuild.m4
@@ -1 +1 @@
-6644
+6645