liblog: split out transports into separate files

(cherry pick from commit 018a96d03f0d452bf078084eedcd5693da42308d)

Create config_logger, logger and logger_read to house the log
interfaces. Add fake_logger, logd_logger and pmsg_logger to
house the write and read transports. Allows for an easier and
direct path to add new transports to the library.

SideEffects: None, logger benchmark performance unaffected

Bug: 27176738
Bug: 27405083
Change-Id: I01b38637334a5242905c8c89f6ab0a92e2540008
diff --git a/liblog/config_write.c b/liblog/config_write.c
new file mode 100644
index 0000000..d689f63
--- /dev/null
+++ b/liblog/config_write.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include "config_write.h"
+#include "logger.h"
+
+LIBLOG_HIDDEN struct listnode __android_log_transport_write =
+    { &__android_log_transport_write, &__android_log_transport_write };
+LIBLOG_HIDDEN struct listnode __android_log_persist_write =
+    { &__android_log_persist_write, &__android_log_persist_write};
+
+static void __android_log_add_transport(
+        struct listnode *list, struct android_log_transport_write *transport) {
+    size_t i;
+
+    /* Try to keep one functioning transport for each log buffer id */
+    for (i = LOG_ID_MIN; i < LOG_ID_MAX; i++) {
+        struct android_log_transport_write *transp;
+
+        if (list_empty(list)) {
+            if (!transport->available || ((*transport->available)(i) >= 0)) {
+                list_add_tail(list, &transport->node);
+                return;
+            }
+        } else {
+            write_transport_for_each(transp, list) {
+                if (!transp->available) {
+                    return;
+                }
+                if (((*transp->available)(i) < 0) &&
+                        (!transport->available ||
+                            ((*transport->available)(i) >= 0))) {
+                    list_add_tail(list, &transport->node);
+                    return;
+                }
+            }
+        }
+    }
+}
+
+LIBLOG_HIDDEN void __android_log_config_write() {
+#if (FAKE_LOG_DEVICE == 0)
+    extern struct android_log_transport_write logdLoggerWrite;
+    extern struct android_log_transport_write pmsgLoggerWrite;
+
+    __android_log_add_transport(&__android_log_transport_write, &logdLoggerWrite);
+    __android_log_add_transport(&__android_log_persist_write, &pmsgLoggerWrite);
+#else
+    extern struct android_log_transport_write fakeLoggerWrite;
+
+    __android_log_add_transport(&__android_log_transport_write, &fakeLoggerWrite);
+#endif
+}