10 files changed, 168 insertions, 101 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 502a6172..d3266e2f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -173,6 +173,8 @@ set(toxcore_SOURCES ${toxcore_SOURCES}
   toxcore/logger.h
   toxcore/network.c
   toxcore/network.h
+  toxcore/state.c
+  toxcore/state.h
   toxcore/util.c
   toxcore/util.h)
 
diff --git a/other/monolith.h b/other/monolith.h
index 42b6b6be..426ba0d9 100644
--- a/other/monolith.h
+++ b/other/monolith.h
@@ -20,6 +20,7 @@
 #include "../toxcore/onion_client.c"
 #include "../toxcore/ping.c"
 #include "../toxcore/ping_array.c"
+#include "../toxcore/state.c"
 #include "../toxcore/tox_api.c"
 #include "../toxcore/util.c"
 
diff --git a/toxcore/BUILD.bazel b/toxcore/BUILD.bazel
index 1d43d828..381a1255 100644
--- a/toxcore/BUILD.bazel
+++ b/toxcore/BUILD.bazel
@@ -52,6 +52,13 @@ cc_library(
 )
 
 cc_library(
+    name = "state",
+    srcs = ["state.c"],
+    hdrs = ["state.h"],
+    deps = [":logger"],
+)
+
+cc_library(
     name = "network",
     srcs = [
         "network.c",
@@ -106,6 +113,7 @@ cc_library(
         ":crypto_core",
         ":logger",
         ":ping_array",
+        ":state",
     ],
 )
 
@@ -190,7 +198,10 @@ cc_library(
     srcs = ["Messenger.c"],
     hdrs = ["Messenger.h"],
     visibility = ["//c-toxcore/toxav:__pkg__"],
-    deps = [":friend_requests"],
+    deps = [
+        ":friend_requests",
+        ":state",
+    ],
 )
 
 cc_library(
diff --git a/toxcore/DHT.c b/toxcore/DHT.c
index 6c104a73..fe3c1159 100644
--- a/toxcore/DHT.c
+++ b/toxcore/DHT.c
@@ -31,6 +31,7 @@
 #include "logger.h"
 #include "network.h"
 #include "ping.h"
+#include "state.h"
 #include "util.h"
 
 #include <assert.h>
@@ -2887,7 +2888,7 @@ int dht_connect_after_load(DHT *dht)
     return 0;
 }
 
-static int dht_load_state_callback(void *outer, const uint8_t *data, uint32_t length, uint16_t type)
+static State_Load_Status dht_load_state_callback(void *outer, const uint8_t *data, uint32_t length, uint16_t type)
 {
     DHT *dht = (DHT *)outer;
 
@@ -2918,7 +2919,7 @@ static int dht_load_state_callback(void *outer, const uint8_t *data, uint32_t le
             break;
     }
 
-    return 0;
+    return STATE_LOAD_STATUS_CONTINUE;
 }
 
 /* Load the DHT from data of size size.
@@ -2935,7 +2936,7 @@ int dht_load(DHT *dht, const uint8_t *data, uint32_t length)
         lendian_to_host32(&data32, data);
 
         if (data32 == DHT_STATE_COOKIE_GLOBAL) {
-            return load_state(dht_load_state_callback, dht->log, dht, data + cookie_len,
+            return state_load(dht->log, dht_load_state_callback, dht, data + cookie_len,
                               length - cookie_len, DHT_STATE_COOKIE_TYPE);
         }
     }
diff --git a/toxcore/Makefile.inc b/toxcore/Makefile.inc
index 2ca25650..4a007a66 100644
--- a/toxcore/Makefile.inc
+++ b/toxcore/Makefile.inc
@@ -27,6 +27,8 @@ libtoxcore_la_SOURCES = ../toxcore/ccompat.h \
                         ../toxcore/Messenger.c \
                         ../toxcore/ping.h \
                         ../toxcore/ping.c \
+                        ../toxcore/state.h \
+                        ../toxcore/state.c \
                         ../toxcore/tox.h \
                         ../toxcore/tox.c \
                         ../toxcore/tox_api.c \
diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index 9014d56d..404827c6 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -35,6 +35,7 @@
 
 #include "logger.h"
 #include "network.h"
+#include "state.h"
 #include "util.h"
 
 static int write_cryptpacket_id(const Messenger *m, int32_t friendnumber, uint8_t packet_id, const uint8_t *data,
@@ -3075,7 +3076,7 @@ void messenger_save(const Messenger *m, uint8_t *data)
     messenger_save_subheader(data, 0, MESSENGER_STATE_TYPE_END);
 }
 
-static int messenger_load_state_callback(void *outer, const uint8_t *data, uint32_t length, uint16_t type)
+static State_Load_Status messenger_load_state_callback(void *outer, const uint8_t *data, uint32_t length, uint16_t type)
 {
     Messenger *m = (Messenger *)outer;
 
@@ -3086,10 +3087,10 @@ static int messenger_load_state_callback(void *outer, const uint8_t *data, uint3
                 load_secret_key(m->net_crypto, (&data[sizeof(uint32_t)]) + CRYPTO_PUBLIC_KEY_SIZE);
 
                 if (public_key_cmp((&data[sizeof(uint32_t)]), nc_get_self_public_key(m->net_crypto)) != 0) {
-                    return -1;
+                    return STATE_LOAD_STATUS_ERROR;
                 }
             } else {
-                return -1;    /* critical */
+                return STATE_LOAD_STATUS_ERROR;    /* critical */
             }
 
             break;
@@ -3152,10 +3153,10 @@ static int messenger_load_state_callback(void *outer, const uint8_t *data, uint3
 
         case MESSENGER_STATE_TYPE_END: {
             if (length != 0) {
-                return -1;
+                return STATE_LOAD_STATUS_ERROR;
             }
 
-            return -2;
+            return STATE_LOAD_STATUS_END;
         }
 
         default:
@@ -3164,7 +3165,7 @@ static int messenger_load_state_callback(void *outer, const uint8_t *data, uint3
             break;
     }
 
-    return 0;
+    return STATE_LOAD_STATUS_CONTINUE;
 }
 
 /* Load the messenger from data of size length. */
@@ -3181,7 +3182,7 @@ int messenger_load(Messenger *m, const uint8_t *data, uint32_t length)
     lendian_to_host32(data32 + 1, data + sizeof(uint32_t));
 
     if (!data32[0] && (data32[1] == MESSENGER_STATE_COOKIE_GLOBAL)) {
-        return load_state(messenger_load_state_callback, m->log, m, data + cookie_len,
+        return state_load(m->log, messenger_load_state_callback, m, data + cookie_len,
                           length - cookie_len, MESSENGER_STATE_COOKIE_TYPE);
     }
 
diff --git a/toxcore/state.c b/toxcore/state.c
new file mode 100644
index 00000000..8da061f4
--- /dev/null
+++ b/toxcore/state.c
@@ -0,0 +1,90 @@
+#include "state.h"
+
+#include <string.h>
+
+/* state load/save */
+int state_load(const Logger *log, state_load_cb *state_load_callback, void *outer,
+               const uint8_t *data, uint32_t length, uint16_t cookie_inner)
+{
+    if (state_load_callback == nullptr || data == nullptr) {
+        LOGGER_ERROR(log, "state_load() called with invalid args.\n");
+        return -1;
+    }
+
+
+    const uint32_t size_head = sizeof(uint32_t) * 2;
+
+    while (length >= size_head) {
+        uint32_t length_sub;
+        lendian_to_host32(&length_sub, data);
+
+        uint32_t cookie_type;
+        lendian_to_host32(&cookie_type, data + sizeof(uint32_t));
+
+        data += size_head;
+        length -= size_head;
+
+        if (length < length_sub) {
+            /* file truncated */
+            LOGGER_ERROR(log, "state file too short: %u < %u\n", length, length_sub);
+            return -1;
+        }
+
+        if (lendian_to_host16((cookie_type >> 16)) != cookie_inner) {
+            /* something is not matching up in a bad way, give up */
+            LOGGER_ERROR(log, "state file garbled: %04x != %04x\n", cookie_type >> 16, cookie_inner);
+            return -1;
+        }
+
+        const uint16_t type = lendian_to_host16(cookie_type & 0xFFFF);
+
+        switch (state_load_callback(outer, data, length_sub, type)) {
+            case STATE_LOAD_STATUS_CONTINUE:
+                data += length_sub;
+                length -= length_sub;
+                break;
+
+            case STATE_LOAD_STATUS_ERROR:
+                return -1;
+
+            case STATE_LOAD_STATUS_END:
+                return 0;
+        }
+    }
+
+    if (length != 0) {
+        LOGGER_ERROR(log, "unparsed data in state file of length %u\n", length);
+        return -1;
+    }
+
+    return 0;
+}
+
+uint16_t lendian_to_host16(uint16_t lendian)
+{
+#ifdef WORDS_BIGENDIAN
+    return (lendian << 8) | (lendian >> 8);
+#else
+    return lendian;
+#endif
+}
+
+void host_to_lendian32(uint8_t *dest,  uint32_t num)
+{
+#ifdef WORDS_BIGENDIAN
+    num = ((num << 8) & 0xFF00FF00) | ((num >> 8) & 0xFF00FF);
+    num = (num << 16) | (num >> 16);
+#endif
+    memcpy(dest, &num, sizeof(uint32_t));
+}
+
+void lendian_to_host32(uint32_t *dest, const uint8_t *lendian)
+{
+    uint32_t d;
+    memcpy(&d, lendian, sizeof(uint32_t));
+#ifdef WORDS_BIGENDIAN
+    d = ((d << 8) & 0xFF00FF00) | ((d >> 8) & 0xFF00FF);
+    d = (d << 16) | (d >> 16);
+#endif
+    *dest = d;
+}
diff --git a/toxcore/state.h b/toxcore/state.h
new file mode 100644
index 00000000..3f7ff043
--- /dev/null
+++ b/toxcore/state.h
@@ -0,0 +1,49 @@
+/**
+ * The state module is responsible for parsing the Tox save data format and for
+ * saving state in that format.
+ *
+ * This module provides functions for iterating over serialised data sections
+ * and reading/writing numbers in the correct format (little endian).
+ *
+ * Note that unlike the Tox network protocol, the save data stores its values in
+ * little endian, which is native to most desktop and server architectures in
+ * 2018.
+ */
+#ifndef C_TOXCORE_TOXCORE_STATE_H
+#define C_TOXCORE_TOXCORE_STATE_H
+
+#include "logger.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Returned by the state_load_cb to instruct the loader on what to do next.
+typedef enum State_Load_Status {
+    // Continue loading state data sections.
+    STATE_LOAD_STATUS_CONTINUE,
+    // An error occurred. Stop loading sections.
+    STATE_LOAD_STATUS_ERROR,
+    // We're at the end of the save data, terminate loading successfully.
+    STATE_LOAD_STATUS_END,
+} State_Load_Status;
+
+typedef State_Load_Status state_load_cb(void *outer, const uint8_t *data, uint32_t len, uint16_t type);
+
+// state load/save
+int state_load(const Logger *log, state_load_cb *state_load_callback, void *outer,
+               const uint8_t *data, uint32_t length, uint16_t cookie_inner);
+
+// Utilities for state data serialisation.
+
+uint16_t lendian_to_host16(uint16_t lendian);
+#define host_tolendian16(x) lendian_to_host16(x)
+
+void host_to_lendian32(uint8_t *dest, uint32_t num);
+void lendian_to_host32(uint32_t *dest, const uint8_t *lendian);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif // C_TOXCORE_TOXCORE_STATE_H
diff --git a/toxcore/util.c b/toxcore/util.c
index 57d1762e..aa2786dd 100644
--- a/toxcore/util.c
+++ b/toxcore/util.c
@@ -92,85 +92,6 @@ void host_to_net(uint8_t *num, uint16_t numbytes)
 #endif
 }
 
-uint16_t lendian_to_host16(uint16_t lendian)
-{
-#ifdef WORDS_BIGENDIAN
-    return (lendian << 8) | (lendian >> 8);
-#else
-    return lendian;
-#endif
-}
-
-void host_to_lendian32(uint8_t *dest,  uint32_t num)
-{
-#ifdef WORDS_BIGENDIAN
-    num = ((num << 8) & 0xFF00FF00) | ((num >> 8) & 0xFF00FF);
-    num = (num << 16) | (num >> 16);
-#endif
-    memcpy(dest, &num, sizeof(uint32_t));
-}
-
-void lendian_to_host32(uint32_t *dest, const uint8_t *lendian)
-{
-    uint32_t d;
-    memcpy(&d, lendian, sizeof(uint32_t));
-#ifdef WORDS_BIGENDIAN
-    d = ((d << 8) & 0xFF00FF00) | ((d >> 8) & 0xFF00FF);
-    d = (d << 16) | (d >> 16);
-#endif
-    *dest = d;
-}
-
-/* state load/save */
-int load_state(load_state_callback_func load_state_callback, const Logger *log, void *outer,
-               const uint8_t *data, uint32_t length, uint16_t cookie_inner)
-{
-    if (!load_state_callback || !data) {
-        LOGGER_ERROR(log, "load_state() called with invalid args.\n");
-        return -1;
-    }
-
-
-    uint32_t length_sub, cookie_type;
-    uint32_t size_head = sizeof(uint32_t) * 2;
-
-    while (length >= size_head) {
-        lendian_to_host32(&length_sub, data);
-        lendian_to_host32(&cookie_type, data + sizeof(length_sub));
-        data += size_head;
-        length -= size_head;
-
-        if (length < length_sub) {
-            /* file truncated */
-            LOGGER_ERROR(log, "state file too short: %u < %u\n", length, length_sub);
-            return -1;
-        }
-
-        if (lendian_to_host16((cookie_type >> 16)) != cookie_inner) {
-            /* something is not matching up in a bad way, give up */
-            LOGGER_ERROR(log, "state file garbled: %04x != %04x\n", (cookie_type >> 16), cookie_inner);
-            return -1;
-        }
-
-        const uint16_t type = lendian_to_host16(cookie_type & 0xFFFF);
-        const int ret = load_state_callback(outer, data, length_sub, type);
-
-        if (ret == -1) {
-            return -1;
-        }
-
-        /* -2 means end of save. */
-        if (ret == -2) {
-            return 0;
-        }
-
-        data += length_sub;
-        length -= length_sub;
-    }
-
-    return length == 0 ? 0 : -1;
-}
-
 int create_recursive_mutex(pthread_mutex_t *mutex)
 {
     pthread_mutexattr_t attr;
diff --git a/toxcore/util.h b/toxcore/util.h
index 3979cefe..c4d55f12 100644
--- a/toxcore/util.h
+++ b/toxcore/util.h
@@ -51,17 +51,6 @@ uint32_t id_copy(uint8_t *dest, const uint8_t *src); /* return value is CLIENT_I
 void host_to_net(uint8_t *num, uint16_t numbytes);
 #define net_to_host(x, y) host_to_net(x, y)
 
-uint16_t lendian_to_host16(uint16_t lendian);
-#define host_tolendian16(x) lendian_to_host16(x)
-
-void host_to_lendian32(uint8_t *dest,  uint32_t num);
-void lendian_to_host32(uint32_t *dest, const uint8_t *lendian);
-
-/* state load/save */
-typedef int (*load_state_callback_func)(void *outer, const uint8_t *data, uint32_t len, uint16_t type);
-int load_state(load_state_callback_func load_state_callback, const Logger *log, void *outer,
-               const uint8_t *data, uint32_t length, uint16_t cookie_inner);
-
 /* Returns -1 if failed or 0 if success */
 int create_recursive_mutex(pthread_mutex_t *mutex);