From c2f8441572b3bec920522ca6ddff90c7ce23c6c3 Mon Sep 17 00:00:00 2001
From: Andrew Chambers <ac@acha.ninja>
Date: Mon, 30 Dec 2019 11:57:34 +1300
Subject: [PATCH] Add file/temp.

---
 src/core/io.c     | 15 +++++++++++++++
 test/suite7.janet |  6 ++++++
 2 files changed, 21 insertions(+)

diff --git a/src/core/io.c b/src/core/io.c
index b998e1a7..c84b85a9 100644
--- a/src/core/io.c
+++ b/src/core/io.c
@@ -136,6 +136,15 @@ static Janet cfun_io_popen(int32_t argc, Janet *argv) {
 }
 #endif
 
+static Janet cfun_io_temp(int32_t argc, Janet *argv) {
+    (void)argv;
+    janet_fixarity(argc, 0);
+    FILE *tmp = tmpfile();
+    if (!tmp)
+      janet_panicf("unable to create temporary file - %s", strerror(errno));
+    return janet_makefile(tmp, JANET_FILE_WRITE|JANET_FILE_READ|JANET_FILE_BINARY);
+}
+
 static Janet cfun_io_fopen(int32_t argc, Janet *argv) {
     janet_arity(argc, 1, 2);
     const uint8_t *fname = janet_getstring(argv, 0);
@@ -566,6 +575,12 @@ static const JanetReg io_cfuns[] = {
         "eprinf", cfun_io_eprinf,
         JDOC("(eprinf fmt & xs)\n\n"
              "Like eprintf but with no trailing newline.")
+    },
+     {
+        "file/temp", cfun_io_temp,
+        JDOC("(file/temp)\n\n"
+             "Open an anonymous temporary file that is removed on close."
+             "Raises an error on failure.")
     },
     {
         "file/open", cfun_io_fopen,
diff --git a/test/suite7.janet b/test/suite7.janet
index f7efb9a7..29e0561d 100644
--- a/test/suite7.janet
+++ b/test/suite7.janet
@@ -277,4 +277,10 @@
 
 (assert (= (constantly) (constantly)) "comptime 1")
 
+(with [f (file/temp)]
+  (file/write f "foo\n")
+  (file/flush f)
+  (file/seek f :set 0)
+  (assert (= (string (file/read f :all)) "foo\n") "temp files work"))
+
 (end-suite)