feature: added the 'ngx.shared.get_info()' API when compiled with debug.

This replaces lua-nginx-module's ngx_http_lua_fake_shm_module for the
`t/148-fake-shm-zone.t` and `t/149-hup-fake-shm-zone.t` test suites.

Author: thibaultcha

src/meta/ngx_meta_lua_shdict.c

@@ -28,6 +28,9 @@ static ngx_inline ngx_queue_t *
     size_t len);
 static int ngx_meta_lua_shdict_expire(ngx_meta_lua_shdict_ctx_t *ctx,
     ngx_uint_t n);
+#if (NGX_DEBUG)
+static int ngx_meta_lua_shdict_get_info(lua_State *L);
+#endif
 static int ngx_meta_lua_shdict_push_helper(lua_State *L, int flags);
 static int ngx_meta_lua_shdict_pop_helper(lua_State *L, int flags);
 static int ngx_meta_lua_shdict_flush_expired(lua_State *L);
@@ -210,9 +213,16 @@ ngx_meta_lua_shdict_init_zone(ngx_shm_zone_t *shm_zone, void *data)
 
     ctx = shm_zone->data;
 
+#if (NGX_DEBUG)
+    ctx->isinit = 1;
+#endif
+
     if (octx) {
         ctx->sh = octx->sh;
         ctx->shpool = octx->shpool;
+#if (NGX_DEBUG)
+        ctx->isold = 1;
+#endif
 
         return NGX_OK;
     }
@@ -340,6 +350,11 @@ ngx_meta_lua_inject_shdict_api(lua_State *L, ngx_cycle_t *cycle, void *tag)
         lua_pushcfunction(L, ngx_meta_lua_shdict_get_keys);
         lua_setfield(L, -2, "get_keys");
 
+#if (NGX_DEBUG)
+        lua_pushcfunction(L, ngx_meta_lua_shdict_get_info);
+        lua_setfield(L, -2, "get_info");
+#endif
+
         lua_pushvalue(L, -1); /* shared mt mt */
         lua_setfield(L, -2, "__index"); /* shared mt */
 
@@ -1282,6 +1297,39 @@ ngx_meta_lua_shdict_llen(lua_State *L)
 }
 
 
+#if (NGX_DEBUG)
+static int
+ngx_meta_lua_shdict_get_info(lua_State *L)
+{
+    ngx_int_t                         n;
+    ngx_shm_zone_t                   *zone;
+    ngx_meta_lua_shdict_ctx_t        *ctx;
+
+    n = lua_gettop(L);
+
+    if (n != 1) {
+        return luaL_error(L, "expecting exactly one argument, but seen %d", n);
+    }
+
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    zone = ngx_meta_lua_shdict_get_zone(L, 1);
+    if (zone == NULL) {
+        return luaL_error(L, "bad \"zone\" argument");
+    }
+
+    ctx = (ngx_meta_lua_shdict_ctx_t *) zone->data;
+
+    lua_pushlstring(L, (char *) zone->shm.name.data, zone->shm.name.len);
+    lua_pushnumber(L, zone->shm.size);
+    lua_pushboolean(L, ctx->isinit);
+    lua_pushboolean(L, ctx->isold);
+
+    return 4;
+}
+#endif
+
+
 ngx_shm_zone_t *
 ngx_meta_lua_ffi_shdict_udata_to_zone(void *zone_udata)
 {

src/meta/ngx_meta_lua_shdict.h

@@ -38,6 +38,10 @@ typedef struct {
 
 
 typedef struct {
+#if (NGX_DEBUG)
+    ngx_int_t                    isold;
+    ngx_int_t                    isinit;
+#endif
     ngx_str_t                    name;
     ngx_meta_lua_shdict_shctx_t *sh;
     ngx_slab_pool_t             *shpool;