Refactor btsnoop and stack config into modules

Moves stack config out of the combined bte_config, and into
its own module.

Makes btsnoop more self sufficient and removes uneccessary
levels of indirection.

Refactor logging slightly into a (temporary) module to disassociate
from the direct calls from config. Eliminates some useless stuff in
the module as well.
diff --git a/main/stack_config.c b/main/stack_config.c
new file mode 100644
index 0000000..a568c23
--- /dev/null
+++ b/main/stack_config.c
@@ -0,0 +1,93 @@
+/******************************************************************************
+ *
+ *  Copyright (C) 2014 Google, Inc.
+ *
+ *  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.
+ *
+ ******************************************************************************/
+
+#define LOG_TAG "bt_stack_config"
+
+#include <assert.h>
+#include <utils/Log.h>
+
+#include "future.h"
+#include "stack_config.h"
+
+const char *BTSNOOP_LOG_PATH_KEY = "BtSnoopFileName";
+const char *BTSNOOP_TURNED_ON_KEY = "BtSnoopLogOutput";
+const char *TRACE_CONFIG_ENABLED_KEY = "TraceConf";
+
+static config_t *config;
+
+// Module lifecycle functions
+
+static future_t *init() {
+  const char *path = "/etc/bluetooth/bt_stack.conf";
+  assert(path != NULL);
+
+  ALOGI("%s attempt to load stack conf from %s", __func__, path);
+
+  config = config_new(path);
+  if (!config) {
+    ALOGI("%s file >%s< not found", __func__, path);
+    return future_new_immediate(FUTURE_FAIL);
+  }
+
+  return future_new_immediate(FUTURE_SUCCESS);
+}
+
+static future_t *clean_up() {
+  config_free(config);
+  return future_new_immediate(FUTURE_SUCCESS);
+}
+
+const module_t stack_config_module = {
+  .name = STACK_CONFIG_MODULE,
+  .init = init,
+  .start_up = NULL,
+  .shut_down = NULL,
+  .clean_up = clean_up,
+  .dependencies = {
+    NULL
+  }
+};
+
+// Interface functions
+
+static const char *get_btsnoop_log_path(void) {
+  return config_get_string(config, CONFIG_DEFAULT_SECTION, BTSNOOP_LOG_PATH_KEY, "/data/misc/bluedroid/btsnoop_hci.log");
+}
+
+static bool get_btsnoop_turned_on(void) {
+  return config_get_bool(config, CONFIG_DEFAULT_SECTION, BTSNOOP_TURNED_ON_KEY, false);
+}
+
+static bool get_trace_config_enabled(void) {
+  return config_get_bool(config, CONFIG_DEFAULT_SECTION, TRACE_CONFIG_ENABLED_KEY, false);
+}
+
+static config_t *get_all(void) {
+  return config;
+}
+
+const stack_config_t interface = {
+  get_btsnoop_log_path,
+  get_btsnoop_turned_on,
+  get_trace_config_enabled,
+  get_all
+};
+
+const stack_config_t *stack_config_get_interface() {
+  return &interface;
+}