lib/linux: implement app::store using sqlite/json/basedir

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/linux/linux.nit b/lib/linux/linux.nit
index 8b90102..b106d62 100644 (file)
--- a/lib/linux/linux.nit
+++ b/lib/linux/linux.nit
@@ -18,3 +18,4 @@
 module linux
 
 import app
+private import linux_data_store

diff --git a/lib/linux/linux_data_store.nit b/lib/linux/linux_data_store.nit
new file mode 100644 (file)
index 0000000..b7cedea
--- /dev/null
+++ b/lib/linux/linux_data_store.nit
@@ -0,0 +1,108 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Copyright 2014 Alexis Laferrière <alexis.laf@xymus.net>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module linux_data_store
+
+import app::data_store
+private import xdg_basedir
+private import sqlite3
+private import json_serialization
+
+redef class App
+       redef var data_store = new LinuxStore
+end
+
+private class LinuxStore
+       super DataStore
+
+       # File path of the Sqlite3 DB file
+       fun db_file: String do return "data_store.db"
+
+       # Sqlite3 table used
+       fun db_table: String do return "data_store"
+
+       private var db_cache: nullable Sqlite3DB = null
+
+       # Database to use to implement the `DataStore`
+       fun db: nullable Sqlite3DB
+       do
+               var db = db_cache
+               if db != null then return db
+
+               # Find DB path
+               var config_home = xdg_basedir.config_home.to_s
+               var config_dir = config_home.join_path(sys.program_name.basename(""))
+               if not config_dir.file_exists then config_dir.mkdir
+               var db_path = config_dir.join_path(db_file)
+
+               # Open DB connection
+               db = new Sqlite3DB.open(db_path)
+               if not db.is_open then
+                       app.log_error "Data store unavaible, cannot load/save data. (at '{db_path}' with '{db.error or else "unknown"}')"
+                       return null
+               end
+
+               # Create DB table
+               db.create_table "IF NOT EXISTS {db_table} (key TEXT PRIMARY KEY, value TEXT)"
+
+               db_cache = db
+               return db
+       end
+
+       redef fun [](key)
+       do
+               # Get DB
+               var db = self.db
+               if db == null then return null
+
+               # Prepare SELECT statement
+               var stmt = db.select("* FROM {db_table} WHERE key == {key.to_sql_string}")
+
+               # Execute statment
+               for row in stmt do
+                       # Get from statement
+                       var serialized = row[1].to_s
+                       stmt.close
+
+                       # Deserialize
+                       var deserializer = new JsonDeserializer(serialized)
+                       var deserialized = deserializer.deserialize
+
+                       return deserialized
+               end
+
+               stmt.close
+               return null
+       end
+
+       redef fun []=(key, value)
+       do
+               # Get DB
+               var db = self.db
+               if db == null then return
+
+               # Serialize
+               var stream = new StringOStream
+               var serializer = new JsonSerializer(stream)
+               serializer.serialize value
+               var serialized = stream.to_s
+
+               # Save in DB
+               db.execute "BEGIN TRANSACTION"
+               db.insert "OR REPLACE INTO {db_table} VALUES({key.to_sql_string}, {serialized.to_sql_string})"
+               db.execute "COMMIT"
+       end
+end