From 135715bf0ae4bc8901c2d352e55e0d71a4bc21f1 Mon Sep 17 00:00:00 2001
From: Maas-Maarten Zeeman <mmzeeman@xs4all.nl>
Date: Sun, 22 May 2022 22:19:30 +0200
Subject: [PATCH] Added extra function to return a map with error information

---
 c_src/esqlite3_nif.c | 41 ++++++++++++++++++++++++++++++++++++++++-
 src/esqlite3.erl     | 12 +++++++++++-
 src/esqlite3_nif.erl | 10 ++++++++++
 3 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/c_src/esqlite3_nif.c b/c_src/esqlite3_nif.c
index fcf44a7..e082db2 100644
--- a/c_src/esqlite3_nif.c
+++ b/c_src/esqlite3_nif.c
@@ -282,7 +282,8 @@ make_extended_error_tuple(ErlNifEnv *env, int code) {
             /* internal use only */
             return make_two_atom_tuple(env, "ok", "symlink");
     }
-    return enif_make_tuple2(env, make_atom(env, "error"), enif_make_int(env, code));
+
+    return enif_make_tuple2(env, make_atom(env, "code"), enif_make_int(env, code));
 }
 
 static const char *
@@ -614,6 +615,42 @@ esqlite_close(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     return make_atom(env, "ok");
 }
 
+/*
+ * Return a description of the last occurred error.
+ */
+static ERL_NIF_TERM
+esqlite_error_info(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
+{
+    esqlite3 *conn;
+    int rc;
+
+    if(argc != 1) {
+        return enif_make_badarg(env);
+    }
+
+    if(!enif_get_resource(env, argv[0], esqlite3_type, (void **) &conn)) {
+        return enif_make_badarg(env);
+    }
+
+    if(conn->db == NULL) {
+        enif_make_badarg(env);
+    }
+
+    int code = sqlite3_extended_errcode(conn->db);
+    int extended_code = sqlite3_extended_errcode(conn->db);
+    const char *errstr = sqlite3_errstr(extended_code);
+    const char *errmsg = sqlite3_errmsg(conn->db);
+
+    ERL_NIF_TERM info = enif_make_new_map(env);
+    enif_make_map_put(env, info, make_atom(env, "errcode"), enif_make_int(env, code), &info);
+    enif_make_map_put(env, info, make_atom(env, "extended_errcode"), enif_make_int(env, extended_code), &info);
+    enif_make_map_put(env, info, make_atom(env, "errstr"), make_binary(env, errstr, strlen(errstr)), &info);
+    enif_make_map_put(env, info, make_atom(env, "errmsg"), make_binary(env, errmsg, strlen(errmsg)), &info);
+    enif_make_map_put(env, info, make_atom(env, "error_offset"), enif_make_int(env, sqlite3_error_offset(conn->db)), &info);
+
+    return info;
+}
+
 void
 update_callback(void *arg, int sqlite_operation_type, char const *sqlite_database, char const *sqlite_table, sqlite3_int64 sqlite_rowid)
 {
@@ -1431,6 +1468,8 @@ static ErlNifFunc nif_funcs[] = {
     {"open", 1, esqlite_open, ERL_NIF_DIRTY_JOB_IO_BOUND},
     {"close", 1, esqlite_close, ERL_NIF_DIRTY_JOB_IO_BOUND},
 
+    {"error_info", 1, esqlite_error_info},
+
     /*
      * Other interesting additions... trace.
      * wal_hook triggered after every commit.
diff --git a/src/esqlite3.erl b/src/esqlite3.erl
index fc650dc..2c5aafb 100644
--- a/src/esqlite3.erl
+++ b/src/esqlite3.erl
@@ -19,7 +19,10 @@
 
 %% higher-level export
 -export([
-    open/1, close/1,
+    open/1,
+    close/1,
+
+    error_info/1,
 
     %% db connection functions
     set_update_hook/2,
@@ -136,6 +139,13 @@ open(Filename) ->
 close(#esqlite3{db=Connection}) ->
     esqlite3_nif:close(Connection).
 
+%% @doc Return a description of the last occurred error. 
+-spec error_info(Connection) -> ErrorMsg 
+    when Connection :: esqlite3(),
+         ErrorMsg :: undefined | binary().
+error_info(#esqlite3{db=Connection}) ->
+    esqlite3_nif:error_info(Connection).
+
 
 %% @doc Subscribe to database notifications. When rows are inserted deleted
 %% or updates, the process will receive messages:
diff --git a/src/esqlite3_nif.erl b/src/esqlite3_nif.erl
index e9232ec..58e7496 100644
--- a/src/esqlite3_nif.erl
+++ b/src/esqlite3_nif.erl
@@ -22,6 +22,7 @@
 -export([
     open/1,
     close/1,
+    error_info/1,
 
     set_update_hook/2,
 
@@ -89,6 +90,15 @@ open(_Filename) ->
 close(_Db) ->
     erlang:nif_error(nif_library_not_loaded).
 
+%% @doc Get an error messages for the last occurred error.
+%%
+-spec error_info(Connection) -> ErrorMsg 
+    when Connection :: esqlite3(),
+         ErrorMsg :: map().
+error_info(_Db) ->
+    erlang:nif_error(nif_library_not_loaded).
+
+
 %% @doc Set an update hook
 %%
 -spec set_update_hook(Connection, Pid) -> Result