add lua binding to fetch-freebsd

pkgs/fetch-freebsd/default.nix

@@ -2,6 +2,7 @@
   cmake,
   stdenv,
   openssl,
+  lua,
   fetchFromGitHub
 }: stdenv.mkDerivation {
   pname = "fetch-freebsd";
@@ -17,9 +18,14 @@
     "-DFETCH_LIBRARY=ON"
     "-DUSE_SYSTEM_SSL=ON"
   ];
+  postBuild = ''
+    $CC -shared -o fetch-lua.so ${./lua-glue.c} -I$src -Llibrary -lssl -lfetch -llua
+  '';
   nativeBuildInputs = [ cmake ];
-  buildInputs = [ openssl ];
+  buildInputs = [ lua openssl ];
   postInstall = ''
     rm -r $out/lib/lib*.a
+    mkdir -p $out/lib/lua/${lua.luaversion}
+    install fetch-lua.so  $out/lib/lua/${lua.luaversion}/fetch.so
   '';
 }

pkgs/fetch-freebsd/lua-glue.c

@@ -0,0 +1,69 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+#include "fetch.h"
+
+/*
+  FIXME: "By default libfetch allows TLSv1 and newer when negotiating
+  the connecting with the remote peer.  You can change this behavior
+  by setting the SSL_NO_TLS1, SSL_NO_TLS1_1 and SSL_NO_TLS1_2
+  environment variables to disable TLS 1.0, 1.1 and 1.2 respectively."
+*/
+
+int lp_error(lua_State *L, int code, char *message) {
+    lua_pushnil(L);
+    lua_pushinteger(L, code);
+    lua_pushlstring(L, message, strlen(message));
+    return 3;
+}
+
+int lp_fetched(lua_State *L, FXRETTYPE fp, struct url_stat *stat) {
+    void * content = malloc(stat->size);
+    size_t bytes_read;
+    es_read(fp, content,  stat->size, &bytes_read);
+
+    if(bytes_read != stat->size) {
+	lp_error(L, -1, "bytes read does not match content-length");
+    }
+    lua_pushlstring(L, (const char *) content, stat->size);
+    lua_newtable(L);
+    lua_pushliteral(L, "last-modified");
+    lua_pushinteger(L, stat->mtime);
+    lua_settable(L, -3);
+
+    return 2;
+}
+
+int lp_fetch(lua_State *L) {
+    const char * url_string = luaL_checkstring(L, 1);
+    const char * flags = luaL_optstring(L, 2, "");
+    time_t if_modified_since = luaL_optinteger(L, 3, 0);
+
+    struct url *url = fetchParseURL(url_string);
+    if(url == NULL) {
+	return lp_error(L, -1, "url not parseable");
+    }
+    url->ims_time = if_modified_since;
+    struct url_stat stat;
+
+    FXRETTYPE fp = fetchXGet(url, &stat, flags);
+    fetchFreeURL(url);
+    if(fp == NULL) {
+	return lp_error(L, fetchLastErrCode, fetchLastErrString);
+    }
+    return lp_fetched(L, fp, &stat);
+}
+
+static const struct luaL_Reg funcs [] = {
+    {"fetch", lp_fetch},
+    {NULL, NULL}  /* sentinel */
+};
+
+
+int luaopen_fetch (lua_State *L) {
+    luaL_newlib(L, funcs);
+    return 1;
+}