feat(p6-batch): CLI/config plumbing for --write-batch/--only-write-batch/--read-batch

src/client/client_cli.c

@@ -604,6 +604,14 @@ static const OptionEntry OPTION_TABLE[] = {
      * any network I/O.  Client-only: the server does not negotiate, it just
      * enforces an exact match. */
     {"--protocol", NULL, OPT_STRING, offsetof(Config, version)},
+    /* Phase 6 residual-batch (client-only): --write-batch=FILE runs the normal
+     * live transfer AND also emits the self-contained batch FILE;
+     * --only-write-batch=FILE emits FILE only (no destination, no server);
+     * --read-batch=FILE applies FILE to the destination (no source, no server).
+     * All three are LOCAL driver flags and never cross the wire. */
+    {"--write-batch", NULL, OPT_STRING, offsetof(Config, write_batch)},
+    {"--only-write-batch", NULL, OPT_STRING, offsetof(Config, only_write_batch)},
+    {"--read-batch", NULL, OPT_STRING, offsetof(Config, read_batch)},
     {"--delete-before", NULL, OPT_FLAG, offsetof(Config, delete_before)},
     {"--delete-during", "--del", OPT_FLAG, offsetof(Config, delete_during)},
     {"--delete-delay", NULL, OPT_FLAG, offsetof(Config, delete_delay)},

src/client/usage.c

@@ -44,6 +44,12 @@ void print_usage(void) {
   printf("  --protocol=NUM       Force the wire protocol version (must equal the current\n");
   printf("                       PROTOCOL_VERSION; FastSync cannot speak older/virtual\n");
   printf("                       wire formats)\n");
+  printf("  --write-batch=FILE    Run the normal live transfer AND also emit a\n");
+  printf("                       self-contained batch file of the whole source tree\n");
+  printf("  --only-write-batch=FILE\n");
+  printf("                       Emit the batch file only (no destination, no server)\n");
+  printf("  --read-batch=FILE     Apply the batch file to the destination (no source, no\n");
+  printf("                       server); takes only the destination as an argument\n");
   printf("  --delete            Delete files on receiver not in source\n");
   printf("                      (default timing: delete only after the whole\n");
   printf("                      transfer has succeeded)\n");

src/shared/config.c

@@ -181,6 +181,9 @@ static void config_set_defaults(Config* config) {
   config->stop_after_mins = 0;
   config->stop_at = 0;
   config->stop_at_set = false;
+  config->write_batch = NULL;
+  config->only_write_batch = NULL;
+  config->read_batch = NULL;
 }
 
 static bool valid_wire_bool(int value) {
@@ -631,6 +634,9 @@ void config_delete(Config* config) {
   free(config->auth_password_hash);
   free(config->password_file);
   free(config->iconv_spec);
+  free(config->write_batch);
+  free(config->only_write_batch);
+  free(config->read_batch);
   free(config->fastsync_server_path);
   for (int i = 0; i < config->exclude_count; i++)
     free(config->exclude_patterns[i]);

src/shared/config.h

@@ -470,6 +470,19 @@ typedef struct Config {
   int stop_after_mins; /* --stop-after=MINS minutes; 0 when unset */
   time_t stop_at;      /* --stop-at=... absolute wall-clock deadline */
   bool stop_at_set;    /* true when --stop-at was given */
+
+  // Phase 6: --write-batch / --only-write-batch / --read-batch
+  /* Client-only residual-batch paths.  A residual batch is a self-contained
+   * single-file record of the whole source tree (full file images using the
+   * chunk codec), independent of any live server.  --write-batch=FILE runs the
+   * normal live transfer AND additionally emits the batch FILE;
+   * --only-write-batch=FILE emits FILE only (no destination, no server);
+   * --read-batch=FILE applies FILE to the destination (no source, no server).
+   * All three are LOCAL to the driving process and are NEVER serialized into
+   * the config frame (the batch paths bypass the transport entirely). */
+  char* write_batch;       /* --write-batch=FILE path, or NULL */
+  char* only_write_batch;  /* --only-write-batch=FILE path, or NULL */
+  char* read_batch;        /* --read-batch=FILE path, or NULL */
 } Config;
 
 /* Phase 5 (remote-option wave): 2.13.0 -> 2.14.0.