Allow getting a tree entry

c_src/tree.c

@@ -0,0 +1,69 @@
+#include <git2.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "oid.h"
+#include "geef.h"
+#include "tree.h"
+
+static int geef_string_bin(ErlNifBinary *bin, const char *str)
+{
+	size_t len;
+
+	len = strlen(str);
+	if (!enif_alloc_binary(len, bin))
+		return -1;
+
+	memcpy(bin->data, str, len);
+
+	return 0;
+}
+
+static ERL_NIF_TERM tree_entry_to_term(ErlNifEnv *env, const git_tree_entry *entry)
+{
+	ErlNifBinary name, oid;
+
+	if (geef_oid_bin(&oid, git_tree_entry_id(entry)) < 0)
+		return atoms.error;
+
+	if (geef_string_bin(&name, git_tree_entry_name(entry)) < 0) {
+		enif_release_binary(&name);
+		return atoms.error;
+	}
+
+	return enif_make_tuple5(env, atoms.ok, enif_make_int(env, git_tree_entry_filemode(entry)),
+				 geef_object_type2atom(git_tree_entry_type(entry)),
+				 enif_make_binary(env, &oid), enif_make_binary(env, &name));
+
+}
+
+ERL_NIF_TERM
+geef_tree_bypath(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
+{
+	char *path;
+	int error;
+	geef_object *obj;
+	ErlNifBinary bin;
+	git_tree_entry *entry;
+
+	if (!enif_get_resource(env, argv[0], geef_object_type, (void **) &obj))
+		return enif_make_badarg(env);
+
+	if (!enif_inspect_iolist_as_binary(env, argv[1], &bin))
+		return enif_make_badarg(env);
+
+	path = malloc(bin.size + 1);
+	if (!path)
+		return atoms.error;
+
+	memcpy(path, bin.data, bin.size);
+	path[bin.size] = '\0';
+
+	error = git_tree_entry_bypath(&entry, (git_tree *)obj->obj, path);
+	free(path);
+
+	if (error < 0)
+		return geef_error(env);
+
+	return tree_entry_to_term(env, entry);
+}