From bfd9b06249814ad7c4bc47c0f065d6337f87076c Mon Sep 17 00:00:00 2001
From: Laurence Kedward <laurence.kedward@bristol.ac.uk>
Date: Mon, 22 Nov 2021 16:13:01 +0000
Subject: Add: backend_output to manage pretty printing of build progress

---
 src/fpm_backend_console.f90 | 82 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 src/fpm_backend_console.f90

(limited to 'src/fpm_backend_console.f90')

diff --git a/src/fpm_backend_console.f90 b/src/fpm_backend_console.f90
new file mode 100644
index 0000000..4db0cdc
--- /dev/null
+++ b/src/fpm_backend_console.f90
@@ -0,0 +1,82 @@
+module fpm_backend_console
+use iso_fortran_env, only: stdout=>output_unit
+implicit none
+
+private
+public :: console_t
+
+character(len=*), parameter :: ESC = char(27)
+
+type console_t
+    integer :: n_line = 1
+    logical :: plain_mode = .false.
+    character(:), allocatable :: LINE_RESET
+    character(:), allocatable :: LINE_UP
+    character(:), allocatable :: LINE_DOWN
+contains
+    procedure :: init => console_init
+    procedure :: write_line => console_write_line
+    procedure :: update_line => console_update_line
+end type console_t
+
+contains
+
+subroutine console_init(console,plain_mode)
+    class(console_t), intent(out), target :: console
+    logical, intent(in), optional :: plain_mode
+
+    if (present(plain_mode)) then
+        console%plain_mode = plain_mode
+    end if
+
+    if (console%plain_mode) then
+        console%LINE_RESET = ""
+        console%LINE_UP = ""
+        console%LINE_DOWN = ""
+    else
+        console%LINE_RESET = ESC//"[2K"//ESC//"[1G"
+        console%LINE_UP = ESC//"[1A"
+        console%LINE_DOWN = ESC//"[1B"
+    end if
+
+end subroutine console_init
+
+function console_write_line(console,str) result(line)
+    class(console_t), intent(inout), target :: console
+    character(*), intent(in) :: str
+    integer :: line
+
+    !$omp critical
+    line = console%n_line
+
+    write(stdout,*) console%LINE_RESET//str
+
+    console%n_line = console%n_line + 1
+    !$omp end critical
+
+end function console_write_line
+
+subroutine console_update_line(console,line_no,str)
+    class(console_t), intent(in) :: console
+    integer, intent(in) :: line_no
+    character(*), intent(in) :: str
+
+    integer :: n
+
+    !$omp critical
+
+    n = console%n_line - line_no !+ 1 !+ 1
+
+    ! Step back to line
+    write(stdout,'(A)',advance="no") repeat(console%LINE_UP,n)//console%LINE_RESET
+
+    write(stdout,*) str
+
+    ! Step forward to end
+    write(stdout,'(A)',advance="no") repeat(console%LINE_DOWN,n)//console%LINE_RESET
+
+    !$omp end critical
+
+end subroutine console_update_line
+
+end module fpm_backend_console
\ No newline at end of file
-- 
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