adb: extract helper for dumping a packet header.

Test: mma
Change-Id: I3e15296eb917d9df11ca13591d26d3aa54d66412
diff --git a/adb/adb_utils.cpp b/adb/adb_utils.cpp
index 35017f0..437720e 100644
--- a/adb/adb_utils.cpp
+++ b/adb/adb_utils.cpp
@@ -186,6 +186,48 @@
     return line;
 }
 
+std::string dump_header(const amessage* msg) {
+    unsigned command = msg->command;
+    int len = msg->data_length;
+    char cmd[9];
+    char arg0[12], arg1[12];
+    int n;
+
+    for (n = 0; n < 4; n++) {
+        int b = (command >> (n * 8)) & 255;
+        if (b < 32 || b >= 127) break;
+        cmd[n] = (char)b;
+    }
+    if (n == 4) {
+        cmd[4] = 0;
+    } else {
+        // There is some non-ASCII name in the command, so dump the hexadecimal value instead
+        snprintf(cmd, sizeof cmd, "%08x", command);
+    }
+
+    if (msg->arg0 < 256U)
+        snprintf(arg0, sizeof arg0, "%d", msg->arg0);
+    else
+        snprintf(arg0, sizeof arg0, "0x%x", msg->arg0);
+
+    if (msg->arg1 < 256U)
+        snprintf(arg1, sizeof arg1, "%d", msg->arg1);
+    else
+        snprintf(arg1, sizeof arg1, "0x%x", msg->arg1);
+
+    return android::base::StringPrintf("[%s] arg0=%s arg1=%s (len=%d) ", cmd, arg0, arg1, len);
+}
+
+std::string dump_packet(const char* name, const char* func, const apacket* p) {
+    std::string result = name;
+    result += ": ";
+    result += func;
+    result += ": ";
+    result += dump_header(&p->msg);
+    result += dump_hex(p->payload.data(), p->payload.size());
+    return result;
+}
+
 std::string perror_str(const char* msg) {
     return android::base::StringPrintf("%s: %s", msg, strerror(errno));
 }
diff --git a/adb/adb_utils.h b/adb/adb_utils.h
index f6ce8e2..ad83302 100644
--- a/adb/adb_utils.h
+++ b/adb/adb_utils.h
@@ -24,6 +24,8 @@
 
 #include <android-base/macros.h>
 
+#include "adb.h"
+
 int syntax_error(const char*, ...) __attribute__((__format__(__printf__, 1, 2)));
 
 void close_stdin();
@@ -42,6 +44,8 @@
 std::string escape_arg(const std::string& s);
 
 std::string dump_hex(const void* ptr, size_t byte_count);
+std::string dump_header(const amessage* msg);
+std::string dump_packet(const char* name, const char* func, const apacket* p);
 
 std::string perror_str(const char* msg);
 
diff --git a/adb/transport.cpp b/adb/transport.cpp
index 95df490..4c198b9 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -408,42 +408,6 @@
     fd_.reset();
 }
 
-static std::string dump_packet(const char* name, const char* func, apacket* p) {
-    unsigned command = p->msg.command;
-    int len = p->msg.data_length;
-    char cmd[9];
-    char arg0[12], arg1[12];
-    int n;
-
-    for (n = 0; n < 4; n++) {
-        int b = (command >> (n * 8)) & 255;
-        if (b < 32 || b >= 127) break;
-        cmd[n] = (char)b;
-    }
-    if (n == 4) {
-        cmd[4] = 0;
-    } else {
-        /* There is some non-ASCII name in the command, so dump
-            * the hexadecimal value instead */
-        snprintf(cmd, sizeof cmd, "%08x", command);
-    }
-
-    if (p->msg.arg0 < 256U)
-        snprintf(arg0, sizeof arg0, "%d", p->msg.arg0);
-    else
-        snprintf(arg0, sizeof arg0, "0x%x", p->msg.arg0);
-
-    if (p->msg.arg1 < 256U)
-        snprintf(arg1, sizeof arg1, "%d", p->msg.arg1);
-    else
-        snprintf(arg1, sizeof arg1, "0x%x", p->msg.arg1);
-
-    std::string result = android::base::StringPrintf("%s: %s: [%s] arg0=%s arg1=%s (len=%d) ", name,
-                                                     func, cmd, arg0, arg1, len);
-    result += dump_hex(p->payload.data(), p->payload.size());
-    return result;
-}
-
 void send_packet(apacket* p, atransport* t) {
     p->msg.magic = p->msg.command ^ 0xffffffff;
     // compute a checksum for connection/auth packets for compatibility reasons