Make atransport be a real class.

Using non-POD types in atransport means we'll need to start treating
it as a real class (specifically with regards to new/delete rather
than malloc/free).

I've also cleaned up the home grown linked lists for transport_list
and pending_list to just be std::lists. We might want to refactor that
again to be an std::unordered_map keyed on serial, since that seems to
be a common way to search it.

Change-Id: I7f5e23cdc47944a9278099723ca029585fe52105
diff --git a/adb/transport.cpp b/adb/transport.cpp
index 818ed97..379c702 100644
--- a/adb/transport.cpp
+++ b/adb/transport.cpp
@@ -26,6 +26,8 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <list>
+
 #include <base/stringprintf.h>
 
 #include "adb.h"
@@ -33,15 +35,8 @@
 
 static void transport_unref(atransport *t);
 
-static atransport transport_list = {
-    .next = &transport_list,
-    .prev = &transport_list,
-};
-
-static atransport pending_list = {
-    .next = &pending_list,
-    .prev = &pending_list,
-};
+static std::list<atransport*> transport_list;
+static std::list<atransport*> pending_list;
 
 ADB_MUTEX_DEFINE( transport_lock );
 
@@ -553,8 +548,7 @@
         adb_close(t->fd);
 
         adb_mutex_lock(&transport_lock);
-        t->next->prev = t->prev;
-        t->prev->next = t->next;
+        transport_list.remove(t);
         adb_mutex_unlock(&transport_lock);
 
         run_transport_disconnects(t);
@@ -570,8 +564,7 @@
         if (t->devpath)
             free(t->devpath);
 
-        memset(t,0xee,sizeof(atransport));
-        free(t);
+        delete t;
 
         update_transports();
         return;
@@ -582,7 +575,7 @@
         /* initial references are the two threads */
         t->ref_count = 2;
 
-        if(adb_socketpair(s)) {
+        if (adb_socketpair(s)) {
             fatal_errno("cannot open transport socketpair");
         }
 
@@ -608,14 +601,8 @@
     }
 
     adb_mutex_lock(&transport_lock);
-    /* remove from pending list */
-    t->next->prev = t->prev;
-    t->prev->next = t->next;
-    /* put us on the master device list */
-    t->next = &transport_list;
-    t->prev = transport_list.prev;
-    t->next->prev = t;
-    t->prev->next = t;
+    pending_list.remove(t);
+    transport_list.push_front(t);
     adb_mutex_unlock(&transport_lock);
 
     t->disconnects.next = t->disconnects.prev = &t->disconnects;
@@ -740,7 +727,6 @@
 
 atransport* acquire_one_transport(ConnectionState state, TransportType type,
                                   const char* serial, std::string* error_out) {
-    atransport *t;
     atransport *result = NULL;
     int ambiguous = 0;
 
@@ -748,7 +734,7 @@
     if (error_out) *error_out = android::base::StringPrintf("device '%s' not found", serial);
 
     adb_mutex_lock(&transport_lock);
-    for (t = transport_list.next; t != &transport_list; t = t->next) {
+    for (auto t : transport_list) {
         if (t->connection_state == kCsNoPerm) {
             if (error_out) *error_out = "insufficient permissions for device";
             continue;
@@ -866,7 +852,8 @@
     }
 }
 
-static void append_transport(atransport* t, std::string* result, bool long_listing) {
+static void append_transport(const atransport* t, std::string* result,
+                             bool long_listing) {
     const char* serial = t->serial;
     if (!serial || !serial[0]) {
         serial = "(no serial number)";
@@ -890,7 +877,7 @@
 std::string list_transports(bool long_listing) {
     std::string result;
     adb_mutex_lock(&transport_lock);
-    for (atransport* t = transport_list.next; t != &transport_list; t = t->next) {
+    for (const auto t : transport_list) {
         append_transport(t, &result, long_listing);
     }
     adb_mutex_unlock(&transport_lock);
@@ -898,11 +885,10 @@
 }
 
 /* hack for osx */
-void close_usb_devices()
-{
+void close_usb_devices() {
     adb_mutex_lock(&transport_lock);
-    for (atransport* t = transport_list.next; t != &transport_list; t = t->next) {
-        if ( !t->kicked ) {
+    for (auto t : transport_list) {
+        if (!t->kicked) {
             t->kicked = 1;
             t->kick(t);
         }
@@ -911,47 +897,39 @@
 }
 #endif // ADB_HOST
 
-int register_socket_transport(int s, const char *serial, int port, int local)
-{
-    atransport *t = reinterpret_cast<atransport*>(calloc(1, sizeof(atransport)));
-    if (t == nullptr) {
-        return -1;
-    }
-
-    atransport *n;
-    char buff[32];
+int register_socket_transport(int s, const char *serial, int port, int local) {
+    atransport* t = new atransport();
 
     if (!serial) {
-        snprintf(buff, sizeof buff, "T-%p", t);
-        serial = buff;
+        char buf[32];
+        snprintf(buf, sizeof(buf), "T-%p", t);
+        serial = buf;
     }
+
     D("transport: %s init'ing for socket %d, on port %d\n", serial, s, port);
     if (init_socket_transport(t, s, port, local) < 0) {
-        free(t);
+        delete t;
         return -1;
     }
 
     adb_mutex_lock(&transport_lock);
-    for (n = pending_list.next; n != &pending_list; n = n->next) {
-        if (n->serial && !strcmp(serial, n->serial)) {
+    for (auto transport : pending_list) {
+        if (transport->serial && strcmp(serial, transport->serial) == 0) {
             adb_mutex_unlock(&transport_lock);
-            free(t);
+            delete t;
             return -1;
         }
     }
 
-    for (n = transport_list.next; n != &transport_list; n = n->next) {
-        if (n->serial && !strcmp(serial, n->serial)) {
+    for (auto transport : transport_list) {
+        if (transport->serial && strcmp(serial, transport->serial) == 0) {
             adb_mutex_unlock(&transport_lock);
-            free(t);
+            delete t;
             return -1;
         }
     }
 
-    t->next = &pending_list;
-    t->prev = pending_list.prev;
-    t->next->prev = t;
-    t->prev->next = t;
+    pending_list.push_front(t);
     t->serial = strdup(serial);
     adb_mutex_unlock(&transport_lock);
 
@@ -960,95 +938,83 @@
 }
 
 #if ADB_HOST
-atransport *find_transport(const char *serial)
-{
-    atransport *t;
+atransport *find_transport(const char *serial) {
+    atransport* result = nullptr;
 
     adb_mutex_lock(&transport_lock);
-    for(t = transport_list.next; t != &transport_list; t = t->next) {
-        if (t->serial && !strcmp(serial, t->serial)) {
+    for (auto t : transport_list) {
+        if (t->serial && strcmp(serial, t->serial) == 0) {
+            result = t;
             break;
         }
-     }
+    }
     adb_mutex_unlock(&transport_lock);
 
-    if (t != &transport_list)
-        return t;
-    else
-        return 0;
+    return result;
 }
 
 void unregister_transport(atransport *t)
 {
     adb_mutex_lock(&transport_lock);
-    t->next->prev = t->prev;
-    t->prev->next = t->next;
+    transport_list.remove(t);
     adb_mutex_unlock(&transport_lock);
 
     kick_transport(t);
     transport_unref(t);
 }
 
-// unregisters all non-emulator TCP transports
-void unregister_all_tcp_transports()
-{
-    atransport *t, *next;
+// Unregisters all non-emulator TCP transports.
+void unregister_all_tcp_transports() {
     adb_mutex_lock(&transport_lock);
-    for (t = transport_list.next; t != &transport_list; t = next) {
-        next = t->next;
+    for (auto it = transport_list.begin(); it != transport_list.end(); ) {
+        atransport* t = *it;
         if (t->type == kTransportLocal && t->adb_port == 0) {
-            t->next->prev = t->prev;
-            t->prev->next = next;
-            // we cannot call kick_transport when holding transport_lock
-            if (!t->kicked)
-            {
+            // We cannot call kick_transport when holding transport_lock.
+            if (!t->kicked) {
                 t->kicked = 1;
                 t->kick(t);
             }
             transport_unref_locked(t);
+
+            it = transport_list.erase(it);
+        } else {
+            ++it;
         }
-     }
+    }
 
     adb_mutex_unlock(&transport_lock);
 }
 
 #endif
 
-void register_usb_transport(usb_handle *usb, const char *serial, const char *devpath, unsigned writeable)
-{
-    atransport *t = reinterpret_cast<atransport*>(calloc(1, sizeof(atransport)));
-    if (t == nullptr) fatal("cannot allocate USB atransport");
+void register_usb_transport(usb_handle* usb, const char* serial,
+                            const char* devpath, unsigned writeable) {
+    atransport* t = new atransport();
+
     D("transport: %p init'ing for usb_handle %p (sn='%s')\n", t, usb,
       serial ? serial : "");
     init_usb_transport(t, usb, (writeable ? kCsOffline : kCsNoPerm));
     if(serial) {
         t->serial = strdup(serial);
     }
-    if(devpath) {
+
+    if (devpath) {
         t->devpath = strdup(devpath);
     }
 
     adb_mutex_lock(&transport_lock);
-    t->next = &pending_list;
-    t->prev = pending_list.prev;
-    t->next->prev = t;
-    t->prev->next = t;
+    pending_list.push_front(t);
     adb_mutex_unlock(&transport_lock);
 
     register_transport(t);
 }
 
 // This should only be used for transports with connection_state == kCsNoPerm.
-void unregister_usb_transport(usb_handle* usb) {
+void unregister_usb_transport(usb_handle *usb) {
     adb_mutex_lock(&transport_lock);
-    for (atransport* t = transport_list.next; t != &transport_list;
-         t = t->next) {
-        if (t->usb == usb && t->connection_state == kCsNoPerm) {
-            t->next->prev = t->prev;
-            t->prev->next = t->next;
-            break;
-        }
-    }
+    transport_list.remove_if([usb](atransport* t) {
+        return t->usb == usb && t->connection_state == kCsNoPerm;
+    });
     adb_mutex_unlock(&transport_lock);
 }