From fecf69febf0e2e2856717f8d475e98310b95395e Mon Sep 17 00:00:00 2001
From: haskal <haskal@awoo.systems>
Date: Sun, 6 Jun 2021 23:16:08 -0400
Subject: [PATCH] abstract subprocess management

---
 ext-mathml/main.rkt | 26 +++-----------------------
 ext-syntax/main.rkt | 27 ++++-----------------------
 util.rkt            | 30 ++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 46 deletions(-)
 create mode 100644 util.rkt

diff --git a/ext-mathml/main.rkt b/ext-mathml/main.rkt
index e27781c..77eb963 100644
--- a/ext-mathml/main.rkt
+++ b/ext-mathml/main.rkt
@@ -1,7 +1,7 @@
 #lang racket/base
 
-(require racket/list racket/match racket/port racket/runtime-path racket/string
-         xml)
+(require racket/list racket/match racket/runtime-path racket/string xml
+         "../util.rkt")
 
 (define-runtime-path *js-path* "./mathml-render.js")
 
@@ -14,27 +14,7 @@
   (map transform-xexpr xexprs))
 
 (define (run-mathjax source block?)
-  (define-values [proc out in err]
-    (subprocess #f #f #f "/usr/bin/env" "node" (path->string *js-path*)))
-  (define out-str #f)
-  (define err-str "")
-  (define out-reader (thread (λ () (set! out-str (port->string out)))))
-  (define err-reader (thread (λ () (set! err-str (port->string err)))))
-
-  (write-string source in)
-  (flush-output in)
-  (close-output-port in)
-
-  (subprocess-wait proc)
-  (thread-wait out-reader)
-  (thread-wait err-reader)
-
-  (define err-trimmed (string-trim err-str))
-  (unless (string=? "" err-trimmed)
-    (error "mathjax process raised error!" err-trimmed))
-
-  (unless out-str
-    (error "mathjax process didn't return anything!"))
+  (define out-str (run-external (list "/usr/bin/env" "node" (path->string *js-path*)) source))
 
   (match-define (list 'math attrs bodies ...) (string->xexpr out-str))
   `(math ,(cons (list 'display (if block? "block" "inline"))
diff --git a/ext-syntax/main.rkt b/ext-syntax/main.rkt
index eab53d5..0c1c1c7 100644
--- a/ext-syntax/main.rkt
+++ b/ext-syntax/main.rkt
@@ -1,6 +1,7 @@
 #lang racket/base
 
-(require racket/list racket/match racket/port racket/runtime-path racket/string xml)
+(require racket/list racket/match racket/runtime-path racket/string xml
+         "../util.rkt")
 
 (define-runtime-path *python-path* "syntax-render.py")
 (define-runtime-path *css-path* "css")
@@ -14,28 +15,8 @@
   (map transform-xexpr xexprs))
 
 (define (run-pygments lang source)
-  (define-values [proc out in err]
-    (subprocess #f #f #f "/usr/bin/env" "python3" (path->string *python-path*) lang))
-  (define out-str #f)
-  (define err-str "")
-  (define out-reader (thread (λ () (set! out-str (port->string out)))))
-  (define err-reader (thread (λ () (set! err-str (port->string err)))))
-
-  (write-string source in)
-  (flush-output in)
-  (close-output-port in)
-
-  (subprocess-wait proc)
-  (thread-wait out-reader)
-  (thread-wait err-reader)
-
-  (define err-trimmed (string-trim err-str))
-  (unless (string=? "" err-trimmed)
-    (error "pygments process raised error!" err-trimmed))
-
-  (unless out-str
-    (error "pygments process didn't return anything!"))
-
+  (define out-str
+    (run-external (list "/usr/bin/env" "python3" (path->string *python-path*) lang) source))
   (string->xexpr out-str))
 
 (define (transform-xexpr xexpr)
diff --git a/util.rkt b/util.rkt
new file mode 100644
index 0000000..e5b63c4
--- /dev/null
+++ b/util.rkt
@@ -0,0 +1,30 @@
+#lang racket/base
+
+(require racket/string racket/port)
+
+(provide run-external)
+
+(define (run-external argv source)
+  (define-values [proc out in err]
+    (apply subprocess #f #f #f "/usr/bin/env" argv))
+  (define out-str #f)
+  (define err-str "")
+  (define out-reader (thread (λ () (set! out-str (port->string out)))))
+  (define err-reader (thread (λ () (set! err-str (port->string err)))))
+
+  (write-string source in)
+  (flush-output in)
+  (close-output-port in)
+
+  (subprocess-wait proc)
+  (thread-wait out-reader)
+  (thread-wait err-reader)
+
+  (define err-trimmed (string-trim err-str))
+  (unless (string=? "" err-trimmed)
+    (error "child process raised error!" err-trimmed))
+
+  (unless out-str
+    (error "child process didn't return anything!"))
+
+  out-str)