Merge remote-tracking branch 'origin/main' into ci/tier1-review-automation

# Conflicts:
#	src/client/client_send.c
#	src/shared/config.c
#	src/shared/file.c
#	src/shared/file.h
#	src/shared/protocol.h

src/shared/file.c

@@ -10,6 +10,7 @@
 #include <unistd.h>
 
 #include "compression.h"
+#include "delta.h"
 #include "log.h"
 #include "config.h"
 #include "data.h"
@@ -136,13 +137,154 @@ bool file_save_to_disk(const char* root_directory, File* file) {
   return ok;
 }
 
+static void *old_data_from_path(const char *full_path, unsigned long long old_size) {
+  void *data = malloc((size_t)old_size);
+  if (!data) return NULL;
+  FILE *fp = fopen(full_path, "rb");
+  if (!fp) { free(data); return NULL; }
+  size_t nread = fread(data, 1, (size_t)old_size, fp);
+  fclose(fp);
+  if (nread != (size_t)old_size) { free(data); return NULL; }
+  return data;
+}
+
+static File *receive_delta_file(int fd, const Config *config, const char *check_path,
+                                 void *old_data, unsigned long long old_size) {
+  if (!old_data) return NULL;
+
+  DeltaSignature *sig = delta_signature_create(old_data, old_size,
+                                                config->delta_block_size);
+  if (!sig) { free(old_data); return NULL; }
+
+  Data *sig_data = delta_signature_serialize(sig);
+  if (!sig_data) { delta_signature_destroy(sig); free(old_data); return NULL; }
+
+  bool sig_sent = send_status(fd, STATUS_DELTA_SIGNATURE) &&
+                  send_data(fd, sig_data);
+  data_destroy(sig_data);
+
+  if (!sig_sent) { delta_signature_destroy(sig); free(old_data); return NULL; }
+
+  Status resp;
+  if (!receive_status(fd, &resp)) {
+    delta_signature_destroy(sig);
+    free(old_data);
+    return NULL;
+  }
+
+  if (resp == STATUS_DELTA_DATA) {
+    Data *delta_data = receive_data(fd);
+    if (!delta_data) {
+      delta_signature_destroy(sig);
+      free(old_data);
+      send_status(fd, STATUS_ERROR);
+      return NULL;
+    }
+
+    Data *raw_delta = delta_data;
+    if (config->use_compression) {
+      raw_delta = data_decompress(delta_data);
+      data_destroy(delta_data);
+      if (!raw_delta) {
+        free(old_data);
+        delta_signature_destroy(sig);
+        send_status(fd, STATUS_ERROR);
+        return NULL;
+      }
+    }
+
+    Delta *delta = delta_deserialize(raw_delta);
+    data_destroy(raw_delta);
+    if (!delta) {
+      free(old_data);
+      delta_signature_destroy(sig);
+      send_status(fd, STATUS_ERROR);
+      return NULL;
+    }
+
+    void *new_data = delta_apply(old_data, old_size, delta,
+                                  config->delta_block_size);
+    uint64_t new_size = delta->new_file_size;
+    delta_destroy(delta);
+
+    if (!new_data) {
+      free(old_data);
+      delta_signature_destroy(sig);
+      send_status(fd, STATUS_ERROR);
+      return NULL;
+    }
+
+    File *file = file_create(check_path);
+    if (!file) {
+      free(new_data);
+      free(old_data);
+      delta_signature_destroy(sig);
+      send_status(fd, STATUS_ERROR);
+      return NULL;
+    }
+
+    if (config->use_metadata) {
+      int meta_ok = 1;
+      file->metadata = metadata_receive(fd, &meta_ok);
+      if (!meta_ok) {
+        file_destroy(file);
+        free(new_data);
+        free(old_data);
+        delta_signature_destroy(sig);
+        send_status(fd, STATUS_ERROR);
+        return NULL;
+      }
+    }
+
+    data_destroy(file->data);
+    file->data = data_create(new_data, (size_t)new_size);
+
+    free(old_data);
+    delta_signature_destroy(sig);
+    return file;
+  }
+
+  if (resp == STATUS_NEXT) {
+    delta_signature_destroy(sig);
+    free(old_data);
+
+    File *file = file_create(check_path);
+    if (!file) { send_status(fd, STATUS_ERROR); return NULL; }
+
+    if (config->use_metadata) {
+      int meta_ok = 1;
+      file->metadata = metadata_receive(fd, &meta_ok);
+      if (!meta_ok) { file_destroy(file); send_status(fd, STATUS_ERROR); return NULL; }
+    }
+
+    Data *file_data = receive_data(fd);
+    if (file_data == NULL) {
+      file_destroy(file);
+      send_status(fd, STATUS_ERROR);
+      return NULL;
+    }
+
+    if (config->use_compression) {
+      Data *uncompressed = data_decompress(file_data);
+      data_destroy(file_data);
+      if (uncompressed == NULL) { file_destroy(file); send_status(fd, STATUS_ERROR); return NULL; }
+      file_data = uncompressed;
+    }
+
+    data_destroy(file->data);
+    file->data = file_data;
+    return file;
+  }
+
+  delta_signature_destroy(sig);
+  free(old_data);
+  return NULL;
+}
+
 File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
   *skipped = false;
   char* check_path = receive_str(fd);
-  if (check_path == NULL) {
-    send_status(fd, STATUS_ERROR);
-    return NULL;
-  }
+  if (check_path == NULL) { send_status(fd, STATUS_ERROR); return NULL; }
 
   unsigned long long check_size;
   long long check_mtime;
@@ -155,34 +297,48 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
 
   char* full_path = path_cat(config->receive_root_directory, check_path);
   struct stat st;
-  bool match = false;
-  if (full_path && stat(full_path, &st) == 0 && (unsigned long long)st.st_size == check_size &&
-      (long long)st.st_mtime == check_mtime) {
-    match = true;
-  }
-  free(full_path);
+  bool has_old_file = (full_path && stat(full_path, &st) == 0);
+  unsigned long long old_size = has_old_file ? (unsigned long long)st.st_size : 0;
+
+  bool match = has_old_file &&
+               (unsigned long long)st.st_size == check_size &&
+               (long long)st.st_mtime == check_mtime;
 
   if (match) {
-    if (!send_status(fd, STATUS_OK)) {
-      free(check_path);
-      return NULL;
-    }
+    if (!send_status(fd, STATUS_OK)) { free(full_path); free(check_path); return NULL; }
+    free(full_path);
     free(check_path);
     *skipped = true;
     return NULL;
   }
 
-  if (!send_status(fd, STATUS_NEXT)) {
-    free(check_path);
-    return NULL;
+  bool try_delta = config->use_delta && has_old_file &&
+                   delta_should_attempt(old_size, check_size, config->delta_max_file_size);
+
+  if (try_delta) {
+    void *old_data = old_data_from_path(full_path, old_size);
+    File *delta_file = receive_delta_file(fd, config, check_path,
+                                           old_data, old_size);
+    if (delta_file) {
+      free(full_path);
+      free(check_path);
+      return delta_file;
+    }
+    try_delta = false;
+  }
+
+  if (!try_delta) {
+    if (!send_status(fd, STATUS_NEXT)) {
+      free(full_path);
+      free(check_path);
+      return NULL;
+    }
   }
 
   File* file = file_create(check_path);
   free(check_path);
-  if (file == NULL) {
-    send_status(fd, STATUS_ERROR);
-    return NULL;
-  }
+  free(full_path);
+  if (file == NULL) { send_status(fd, STATUS_ERROR); return NULL; }
 
   if (config->use_metadata) {
     int meta_ok = 1;
@@ -242,11 +398,10 @@ bool to_disk(const char* path, const void* data, unsigned long long data_size) {
   return true;
 }
 
-bool file_send_sendfile(File* file, int file_descriptor, bool use_metadata, bool send_path) {
-  if (send_path && !send_str(file_descriptor, file->path))
-    return false;
-  if (use_metadata && !metadata_send(file_descriptor, file->metadata))
-    return false;
+bool file_send_sendfile(File *file, int file_descriptor, bool use_metadata, int compression_level, bool send_path) {
+  (void)compression_level;
+  if (send_path && !send_str(file_descriptor, file->path)) return false;
+  if (use_metadata && !metadata_send(file_descriptor, file->metadata)) return false;
 
   int fd = open(file->path, O_RDONLY);
   if (fd == -1) {