added tests and fixed bugs

lib/resty/lmdb.lua

@@ -2,48 +2,104 @@ local _M = {}
 
 
 local transaction = require("resty.lmdb.transaction")
+local range = require("resty.lmdb.range")
 local status = require("resty.lmdb.status")
 
 
-do
-    local CACHED_TXN = transaction.begin(1)
+local next = next
+local error = error
+local assert = assert
+local range_page = range.page
 
 
-    function _M.get(key, db)
-        CACHED_TXN:reset()
-        CACHED_TXN:get(key, db)
-        local res, err = CACHED_TXN:commit()
-        if not res then
-            return nil, err
-        end
+local CACHED_TXN = transaction.begin(1)
+
 
-        return CACHED_TXN[1].result
+function _M.get(key, db)
+    CACHED_TXN:reset()
+    CACHED_TXN:get(key, db)
+    local res, err = CACHED_TXN:commit()
+    if not res then
+        return nil, err
     end
 
+    return CACHED_TXN[1].result
+end
 
-    function _M.set(key, value, db)
-        CACHED_TXN:reset()
-        CACHED_TXN:set(key, value, db)
-        local res, err = CACHED_TXN:commit()
-        if not res then
-            return nil, err
-        end
 
-        return true
+function _M.set(key, value, db)
+    CACHED_TXN:reset()
+    CACHED_TXN:set(key, value, db)
+    local res, err = CACHED_TXN:commit()
+    if not res then
+        return nil, err
+    end
+
+    return true
+end
+
+
+function _M.db_drop(delete, db)
+    delete = not not delete
+
+    CACHED_TXN:reset()
+    CACHED_TXN:db_drop(delete, db)
+    local res, err = CACHED_TXN:commit()
+    if not res then
+        return nil, err
     end
 
+    return true
+end
 
-    function _M.db_drop(delete, db)
-        delete = not not delete
 
-        CACHED_TXN:reset()
-        CACHED_TXN:db_drop(delete, db)
-        local res, err = CACHED_TXN:commit()
+function _M.prefix(prefix, db)
+    local res, i, res_n, err_or_more
+    local last = prefix
+
+    return function()
+        ::more::
         if not res then
-            return nil, err
+            -- need to fetch more data
+            res, err_or_more = range_page(last, db)
+            if not res then
+                return nil, err_or_more
+            end
+
+            res_n = #res
+            if res_n == 0 or (i and res_n == 1) then
+                return nil
+            end
+
+            if i then
+                -- not the first call to prefix_page, skip the first key
+                i = 2
+
+            else
+                -- first call to prefix_page
+                i = 1
+            end
+        end
+
+        assert(res_n > 0)
+
+        if i > res_n then
+            if err_or_more then
+                last = res[i - 1].key
+                res = nil
+                goto more
+            end
+
+            -- more = false
+
+            return nil
         end
 
-        return true
+        local key = res[i].key
+        local value = res[i].value
+        i = i + 1
+
+        return key, value
     end
 end
 

lib/resty/lmdb/ffi.lua

@@ -41,5 +41,7 @@ int ngx_lua_resty_lmdb_ffi_env_info(ngx_lua_resty_lmdb_ffi_status_t *lst, char *
 
 
 int ngx_lua_resty_lmdb_ffi_execute(ngx_lua_resty_lmdb_operation_t *ops,
-    size_t n, int need_write, unsigned char *buf, size_t buf_len, char **err);
+    size_t n, int need_write, u_char *buf, size_t buf_len, char **err);
+int ngx_lua_resty_lmdb_ffi_range(ngx_lua_resty_lmdb_operation_t *ops,
+    size_t n, u_char *buf, size_t buf_len, char **err);
 ]])

lib/resty/lmdb/range.lua

@@ -8,24 +8,39 @@ local transaction = require("resty.lmdb.transaction")
 local base = require("resty.core.base")
 
 
+local C = ffi.C
 local DEFAULT_OPS_SIZE = 512
 local DEFAULT_DB = transaction.DEFAULT_DB
-local C = ffi.C
+local NGX_ERROR = ngx.ERROR
+local NGX_AGAIN = ngx.AGAIN
 
 
 local ffi_string = ffi.string
+local ffi_new = ffi.new
 local get_dbi = transaction.get_dbi
 local err_ptr = base.get_errmsg_ptr()
+local get_string_buf = base.get_string_buf
+local get_string_buf_size = base.get_string_buf_size
+local assert = assert
 
 
 function _M.page(start, db)
     local value_buf_size = get_string_buf_size()
     local ops = ffi_new("ngx_lua_resty_lmdb_operation_t[?]", DEFAULT_OPS_SIZE)
 
-    ops[0].opcode = C.NGX_LMDB_OP_GET
-    cop.key.data = start
-    cop.key.len = #start
-    cop.dbi = get_dbi(false, db or DEFAULT_DB)
+    ops[0].opcode = C.NGX_LMDB_OP_PREFIX
+    ops[0].key.data = start
+    ops[0].key.len = #start
+
+    local dbi, err = get_dbi(false, db or DEFAULT_DB)
+    if err then
+        return nil, "unable to open DB for access: " .. err
+
+    elseif not dbi then
+        return nil, "DB " .. lop.db .. " does not exist"
+    end
+
+    ops[0].dbi = dbi
 
 ::again::
     local buf = get_string_buf(value_buf_size, false)
@@ -42,27 +57,28 @@ function _M.page(start, db)
 
     if ret == 0 then
         -- unlikely case
-        return {}
+        return {}, false
     end
 
     assert(ret > 0)
 
     local res = table_new(ret, 0)
 
-    for i = 1, DEFAULT_OPS_SIZE do
+    for i = 1, ret do
         local cop = ops[i - 1]
 
         assert(cop.opcode == C.NGX_LMDB_OP_PREFIX)
 
         local pair = {
             key = ffi_string(cop.key.data, cop.key.len),
-            value = ffi_string(cop.key.data, cop.key.len),
+            value = ffi_string(cop.value.data, cop.value.len),
         }
 
         res[i] = pair
     end
 
-    return res
+    -- if ret == DEFAULT_OPS_SIZE, then it is possible there are more keys
+    return res, ret == DEFAULT_OPS_SIZE
 end
 
 

src/ngx_lua_resty_lmdb_range.c

@@ -61,32 +61,43 @@ int ngx_lua_resty_lmdb_ffi_range(ngx_lua_resty_lmdb_operation_t *ops,
         rc = mdb_cursor_get(cur, &key, &value, i == 0 ? MDB_SET_RANGE : MDB_NEXT);
         if (rc == 0) {
             /* key found, copy result into buf */
-            if (value.mv_size > buf_len) {
+            if (key.mv_size + value.mv_size > buf_len) {
                 mdb_cursor_close(cur);
                 mdb_txn_reset(txn);
 
                 return NGX_AGAIN;
             }
 
+            ops[i].key.data = buf;
+            ops[i].key.len = key.mv_size;
+            buf = ngx_cpymem(buf, key.mv_data, key.mv_size);
+
             ops[i].value.data = buf;
             ops[i].value.len = value.mv_size;
+            buf = ngx_cpymem(buf, value.mv_data, value.mv_size);
+
             ops[i].opcode = NGX_LMDB_OP_PREFIX;
 
-            buf = ngx_cpymem(buf, value.mv_data, value.mv_size);
-            buf_len -= value.mv_size;
+            buf_len -= key.mv_size + value.mv_size;
 
         } else if (rc == MDB_NOTFOUND) {
+            mdb_cursor_close(cur);
+            mdb_txn_reset(txn);
+
             return i;
 
         } else {
             *err = mdb_strerror(rc);
-            goto err;
+
+            mdb_cursor_close(cur);
+            mdb_txn_reset(txn);
+
+            return NGX_ERROR;
         }
     }
 
-err:
     mdb_cursor_close(cur);
     mdb_txn_reset(txn);
 
-    return NGX_ERROR;
+    return i;
 }