jshn: add functionality to read big JSON

The existing read functionality feeds the complete JSON to jshn as a
cmdline argument, leading to `-ash: jshn: Argument list too long`
errors for JSONs bigger than ca. 100KB.

This commit adds the ability to read the JSON directly from a file if
wanted, removing this shell-imposed size limit.

Tested on x86-64 and ar71xx. An mmap()-based solution was also evaluated,
but found to make no performance difference on either platform.

Signed-off-by: Christian Beier <dontmind@freeshell.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/sh/jshn.sh b/sh/jshn.sh
index 1090814..66baccb 100644
--- a/sh/jshn.sh
+++ b/sh/jshn.sh
@@ -180,6 +180,10 @@ json_load() {
 	eval "`jshn -r "$1"`"
 }
 
+json_load_file() {
+	eval "`jshn -R "$1"`"
+}
+
 json_dump() {
 	jshn "$@" ${JSON_PREFIX:+-p "$JSON_PREFIX"} -w 
 }