5 files changed, 95 insertions(+), 2 deletions(-)

M README.md
M include/store.h
M src/api.c
M src/script.c
M src/store.c

@@ 189,3 189,13 @@ These methods are concerned with handling user-input.
 ### Key/Value Store
 
 MoonGem implements an in-memory key/value store accessed via the `mg.store` table.  This feature is useful for establishing state that's persistent across multiple requests.
+
+- `#mg.store`
+  - Returns the number of stored key/value pairs
+- `mg.store.dump([path])`
+  - Writes the contents of the data store in a tab-separated format to a file at `path`, or stdout if `path` is ommitted
+- `mg.store.get_info()`
+  - Returns a table with the following fields:
+    - `length`: The number of stored key/value pairs
+    - `capacity`: The total number of slots allocated
+    - `data_size`: The combined length of all of the stored values, in bytes

@@ 9,6 9,7 @@
 
 typedef struct cell_t {
   uint64_t key;
+  size_t length;
   char* data;
   bool deleted;
 } cell_t;

@@ 1,5 1,6 @@
 #include <lauxlib.h>
 #include <lua.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>


@@ 23,6 24,10 @@
 #define FLD_CERT_FINGERPRINT "fingerprint"
 #define FLD_CERT_EXPIRATION "not_after"
 
+#define FLD_STORE_LENGTH "length"
+#define FLD_STORE_CAPACITY "capacity"
+#define FLD_STORE_DATA_SIZE "data_size"
+
 static void set_interrupt_response(response_t* response, int status,
                                    const char* meta) {
   response->interrupted = true;


@@ 571,3 576,67 @@ int api_get_store_value(lua_State* L) {
 
   return 1;
 }
+
+int api_dump_store(lua_State* L) {
+  lua_settop(L, 1);
+
+  const char* path = lua_tostring(L, 1);
+
+  lua_getfield(L, LUA_REGISTRYINDEX, FLD_STORE);
+  store_t* store = lua_touserdata(L, -1);
+
+  FILE* out = path == NULL ? stdout : fopen(path, "w");
+  if (out == NULL) {
+    luaL_error(L, "Failed to open output stream");
+  } else {
+    fprintf(out, "position\tkey\tlength\tdata\n");
+    for (size_t i = 0; i < store->cell_count; i++) {
+      cell_t* cell = &store->cells[i];
+      if (cell->key == 0 || cell->deleted) {
+        continue;
+      }
+
+      fprintf(out, "%zu\t%zu\t%zu\t%s\n", i, cell->key, cell->length,
+              cell->data);
+    }
+  }
+
+  return 0;
+}
+
+int api_get_store_length(lua_State* L) {
+  lua_getfield(L, LUA_REGISTRYINDEX, FLD_STORE);
+  store_t* store = lua_touserdata(L, -1);
+
+  lua_pushinteger(L, store->stored_count);
+
+  return 1;
+}
+
+int api_get_store_info(lua_State* L) {
+  lua_newtable(L);
+
+  lua_getfield(L, LUA_REGISTRYINDEX, FLD_STORE);
+  store_t* store = lua_touserdata(L, -1);
+
+  lua_pushinteger(L, store->stored_count);
+  lua_setfield(L, -2, FLD_STORE_LENGTH);
+
+  lua_pushinteger(L, store->cell_count);
+  lua_setfield(L, -2, FLD_STORE_CAPACITY);
+
+  size_t total_length = 0;
+  for (size_t i = 0; i < store->cell_count; i++) {
+    cell_t* cell = &store->cells[i];
+    if (cell->key == 0 || cell->deleted) {
+      continue;
+    }
+
+    total_length += cell->length;
+  }
+
+  lua_pushinteger(L, total_length);
+  lua_setfield(L, -2, FLD_STORE_DATA_SIZE);
+
+  return 1;
+}

@@ 59,6 59,9 @@
 
 #define TBL_STORE "store"
 
+#define FUNC_DUMP "dump"
+#define FUNC_INFO "get_info"
+
 #define SCRIPT_BUFFER_SIZE (1 << 16)
 
 static char global_script_buffer[SCRIPT_BUFFER_SIZE];


@@ 119,6 122,9 @@ int api_endblock(lua_State* L);
 /* Key/Value Store */
 int api_set_store_value(lua_State* L);
 int api_get_store_value(lua_State* L);
+int api_dump_store(lua_State* L);
+int api_get_store_length(lua_State* L);
+int api_get_store_info(lua_State* L);
 
 static void set_api_methods(lua_State* L) {
   luaL_Reg methods[] = {{FUNC_SET_PATH, api_set_path},


@@ 167,9 173,13 @@ static void set_api_methods(lua_State* L) {
   luaL_newlib(L, methods);
 
   // set up a table for the key/value store
-  lua_newtable(L);
+  luaL_Reg store_methods[] = {{FUNC_DUMP, api_dump_store},
+                              {FUNC_INFO, api_get_store_info},
+                              {NULL, NULL}};
+  luaL_newlib(L, store_methods);
   luaL_Reg store_metamethods[] = {{"__index", api_get_store_value},
                                   {"__newindex", api_set_store_value},
+                                  {"__len", api_get_store_length},
                                   {NULL, NULL}};
   luaL_newlib(L, store_metamethods);
   lua_setmetatable(L, -2);

@@ 66,6 66,7 @@ static void insert_by_keyhash(store_t* store, uint64_t key, char* data) {
 
   cell->key = key;
   cell->data = data;
+  cell->length = strlen(data);
   cell->deleted = false;
 }
 


@@ 133,12 134,14 @@ bool delete_from_store(store_t* store, char* key) {
     return false;
   }
 
-  target->deleted = true;
   if (target->data != NULL) {
     free(target->data);
     target->data = NULL;
   }
 
+  target->deleted = true;
+  target->length = 0;
+
   --(store->stored_count);
 
   return true;