Adding Android Binder Bridge (abb) utility launched from adbd.

Once launched, abb will listen for incoming Binder cli requests.
Executing in-process provides 6x latency improvement (125ms vs 25ms on
PixelXL) for commands like 'package path'

Intended usage by Android Studio for fast deployment and patching of APKs.

Test: manual
BUG: 111621042

Change-Id: Ica84eb2ec9628efa441ecd627b119f3361feaf9f
diff --git a/adb/daemon/abb.cpp b/adb/daemon/abb.cpp
new file mode 100644
index 0000000..f69babe
--- /dev/null
+++ b/adb/daemon/abb.cpp
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2018 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 "adb.h"
+#include "adb_io.h"
+#include "shell_service.h"
+
+#include "cmd.h"
+
+#include <sys/wait.h>
+
+namespace {
+
+class AdbFdTextOutput : public android::TextOutput {
+  public:
+    explicit AdbFdTextOutput(int fd) : mFD(fd) {}
+
+  private:
+    android::status_t print(const char* txt, size_t len) override {
+        return WriteFdExactly(mFD, txt, len) ? android::OK : -errno;
+    }
+    void moveIndent(int delta) override { /*not implemented*/
+    }
+
+    void pushBundle() override { /*not implemented*/
+    }
+    void popBundle() override { /*not implemented*/
+    }
+
+  private:
+    int mFD;
+};
+
+std::vector<std::string_view> parseCmdArgs(std::string_view args) {
+    std::vector<std::string_view> argv;
+
+    char delim = ABB_ARG_DELIMETER;
+    size_t size = args.size();
+    size_t base = 0;
+    while (base < size) {
+        size_t found;
+        for (found = base; found < size && args[found] && args[found] != delim; ++found)
+            ;
+        if (found > base) {
+            argv.emplace_back(args.substr(base, found - base));
+        }
+        base = found + 1;
+    }
+
+    return argv;
+}
+
+}  // namespace
+
+static int execCmd(std::string_view args, int in, int out, int err) {
+    AdbFdTextOutput oin(out);
+    AdbFdTextOutput oerr(err);
+    return cmdMain(parseCmdArgs(args), oin, oerr, in, out, err, RunMode::kLibrary);
+}
+
+int main(int argc, char* const argv[]) {
+    signal(SIGPIPE, SIG_IGN);
+
+    int fd = STDIN_FILENO;
+    std::string data;
+    while (true) {
+        std::string error;
+        if (!ReadProtocolString(fd, &data, &error)) {
+            PLOG(ERROR) << "Failed to read message: " << error;
+            break;
+        }
+
+        auto result = StartCommandInProcess(std::move(data), &execCmd);
+        if (!SendFileDescriptor(fd, result)) {
+            PLOG(ERROR) << "Failed to send an inprocess fd for command: " << data;
+            break;
+        }
+    }
+}