filters: rewrite colorize in c

Since its introduction, we had multiple issues with the colorize awk
script with regard to non-GNU awk compatibility.

Also, this script is standalone and the color theme must be hard coded
into it. Reading from an external configuration file (aerc's styleset)
from a non-GNU awk is close to impossible (and even far from trivial
with GNU awk).

Rewrite the builtin colorize filter in C to allow getting the color
theme from aerc's active styleset. The theme is configured using the
existing styleset syntax and attributes under a separate [viewer]
section (see examples and man page).

Export the active styleset file path to AERC_STYLESET env var when
invoking the filter command so that colorize can access it and use it.

I have tested compilation (with clang-analyzer and gcc -fanalyzer) and
basic operation on FreeBSD, Fedora (glibc) and Alpine (muslibc). More
tests would probably be required on MacOSX and older Linux distros.
I also added test vectors to give some confidence that this works as
expected. The execution with these vectors passed valgrind
--leak-check=full without errors.

NB: the default theme has changed to be more minimal. Sample stylesets
have more colorful examples. The awk -v theme=xxx option is no longer
supported.

  usage: colorize [-h] [-s FILE] [-f FILE]

  options:
    -h       show this help message
    -s FILE  use styleset file (default $AERC_STYLESET)
    -f FILE  read from filename (default stdin)

Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Bence Ferdinandy <bence@ferdinandy.com>
Acked-by: Moritz Poldrack <moritz@poldrack.dev>

5 files changed, 68 insertions, 0 deletions

diff --git a/stylesets/blue b/stylesets/blue
index 29e165be..7ae019d2 100644
--- a/stylesets/blue
+++ b/stylesets/blue
@@ -45,3 +45,19 @@ default.selected.fg=white
 default.selected.bg=#005f87
 
 completion_default.selected.bg=#005f87
+
+[viewer]
+url.fg=#ffffaf
+url.underline=true
+header.fg=#af87ff
+signature.fg=#af87ff
+diff_meta.fg=#ffffff
+diff_meta.bold=true
+diff_chunk.fg=#00cdcd
+diff_add.fg=#00cd00
+diff_del.fg=#cd0000
+quote_1.fg=#5fafff
+quote_2.fg=#ff8700
+quote_3.fg=#af87ff
+quote_4.fg=#ff5fd7
+quote_x.fg=#808080
diff --git a/stylesets/default b/stylesets/default
index 078920bf..5ee1c4e0 100644
--- a/stylesets/default
+++ b/stylesets/default
@@ -35,3 +35,15 @@ border.reverse = true
 
 selector_focused.reverse=true
 selector_chooser.bold=true
+
+[viewer]
+url.underline=true
+header.bold=true
+signature.dim=true
+diff_meta.bold=true
+diff_chunk.dim=true
+diff_add.fg=2
+diff_del.fg=1
+quote_*.fg=6
+quote_*.dim=true
+quote_1.dim=false
diff --git a/stylesets/dracula b/stylesets/dracula
index 10f21a5e..c400865a 100644
--- a/stylesets/dracula
+++ b/stylesets/dracula
@@ -46,3 +46,15 @@ default.selected.bg=#44475A
 
 completion_default.selected.bg=#44475A
 completion_default.selected.fg=white
+
+[viewer]
+url.underline=true
+header.bold=true
+signature.dim=true
+diff_meta.bold=true
+diff_chunk.dim=true
+diff_add.fg=2
+diff_del.fg=1
+quote_*.fg=6
+quote_*.dim=true
+quote_1.dim=false
diff --git a/stylesets/nord b/stylesets/nord
index 5f5274f7..8f7d5140 100644
--- a/stylesets/nord
+++ b/stylesets/nord
@@ -44,3 +44,15 @@ tab.selected.fg=#2c3441
 
 dirlist_unread.fg=#64A6B3
 dirlist_recent.fg=#64A6B3
+
+[viewer]
+url.underline=true
+header.bold=true
+signature.dim=true
+diff_meta.bold=true
+diff_chunk.dim=true
+diff_add.fg=2
+diff_del.fg=1
+quote_*.fg=6
+quote_*.dim=true
+quote_1.dim=false
diff --git a/stylesets/pink b/stylesets/pink
index 743da359..792771a2 100644
--- a/stylesets/pink
+++ b/stylesets/pink
@@ -47,3 +47,19 @@ default.selected.fg=white
 default.selected.bg=#de4e85
 
 completion_default.selected.bg=#de4e85
+
+[viewer]
+url.fg=#ffffaf
+url.underline=true
+header.fg=#af87ff
+signature.fg=#af87ff
+diff_meta.fg=#ffffff
+diff_meta.bold=true
+diff_chunk.fg=#00cdcd
+diff_add.fg=#00cd00
+diff_del.fg=#cd0000
+quote_1.fg=#5fafff
+quote_2.fg=#ff8700
+quote_3.fg=#af87ff
+quote_4.fg=#ff5fd7
+quote_x.fg=#808080