feat: implement --delay-updates receiver staging and publication

Stage every successfully written file under a private 0700 .fastsync-stage directory inside the receive root and atomically publish all staged files only after the whole protocol stream (manifest/delete handling included) has completed, immediately before the success/outcome frame. On any abort/error before publication nothing is installed and staging is removed; a publish failure aborts the transfer with best-effort cleanup of the remainder (already-published files are not rolled back). Crash leftovers are wiped when the next delayed transfer starts. Wire: new delay_updates config flag (selection-options block), protocol version bumped to 2.6.0, client/server validation rejects --inplace. CLI/usage/validation updated. Works in single-threaded and -m modes (exactly one write_thread stages files; the staged-file registry is mutex-protected; publication runs once after both threads join). --existing/--ignore-existing/--update decide against the final destination at stage time; --backup is deferred to publication. remove_source_files outcomes are only sent after publication so skipped/unpublished sources are never deleted. Default (no flag) behavior is unchanged. Tests: config wire round-trip, CLI parse, --inplace rejection, new test_delay_updates unit suite (27 suites total), and integration TestDelayUpdates covering single/-m parity, incremental reruns, remove source files, receiver-skip ordering, and a deterministic publish-failure abort path.
2026-09-06 13:20:03 +02:00
parent 8577f95550
commit a2a82dd856
19 changed files with 985 additions and 24 deletions
@@ -0,0 +1,283 @@
+#include "test_delay_updates.h"
+#include "config.h"
+#include "delay_updates.h"
+#include "file.h"
+#include "file_receive.h"
+#include "test_utils.h"
+#include "utils.h"
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Recursively remove a test tree (never follows symlinks). */
+static void remove_tree(const char* path) {
+  struct stat st;
+  if (lstat(path, &st) != 0)
+    return;
+  if (S_ISDIR(st.st_mode)) {
+    DIR* dir = opendir(path);
+    if (!dir)
+      return;
+    const struct dirent* entry;
+    while ((entry = readdir(dir)) != NULL) {
+      if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+        continue;
+      char* child = path_cat(path, entry->d_name);
+      if (child) {
+        remove_tree(child);
+        free(child);
+      }
+    }
+    closedir(dir);
+    rmdir(path);
+  } else {
+    unlink(path);
+  }
+}
+
+/* Build a File that carries `content`. */
+static File* make_file(const char* path, const char* content) {
+  File* f = file_create(path);
+  if (!f)
+    return NULL;
+  f->data->data = malloc(strlen(content));
+  if (!f->data->data) {
+    file_destroy(f);
+    return NULL;
+  }
+  memcpy(f->data->data, content, strlen(content));
+  f->data->size = strlen(content);
+  return f;
+}
+
+static char* read_all(const char* path) {
+  FILE* fp = fopen(path, "rb");
+  if (!fp)
+    return NULL;
+  char buf[256] = {0};
+  size_t n = fread(buf, 1, sizeof(buf) - 1, fp);
+  fclose(fp);
+  char* out = malloc(n + 1);
+  if (!out)
+    return NULL;
+  memcpy(out, buf, n);
+  out[n] = '\0';
+  return out;
+}
+
+static void test_delay_updates_no_final_before_publish() {
+  const char* root = "test_delay_tmp";
+  remove_tree(root);
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->delay_updates = true;
+
+  File* f = make_file("sub/file.txt", "staged payload");
+  EXPECT_NOT_NULL(f);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!cfg || !f)
+    goto out;
+
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, cfg), FILE_SAVE_WRITTEN);
+  EXPECT_NOT_NULL(cfg->delay_context);
+
+  const char* final_path = "test_delay_tmp/sub/file.txt";
+  /* Before publication the final destination must not contain the file. */
+  EXPECT_FALSE(file_path_exists_secure(final_path));
+  /* The complete staged copy must live inside the staging tree. */
+  char* staged = path_cat("test_delay_tmp/.fastsync-stage", "/sub/file.txt");
+  EXPECT_NOT_NULL(staged);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (staged) {
+    char* content = read_all(staged);
+    EXPECT_NOT_NULL(content);
+    // cppcheck-suppress knownConditionTrueFalse
+    if (content) {
+      EXPECT_EQ_STR(content, "staged payload");
+      free(content);
+    }
+    free(staged);
+  }
+
+out:
+  file_destroy(f);
+  config_delete(cfg);
+  remove_tree(root);
+}
+
+static void test_delay_updates_publish_installs_files() {
+  const char* root = "test_delay_pub_tmp";
+  remove_tree(root);
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->delay_updates = true;
+
+  File* f = make_file("sub/file.txt", "published payload");
+  EXPECT_NOT_NULL(f);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!cfg || !f)
+    goto out;
+
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, cfg), FILE_SAVE_WRITTEN);
+  const char* final_path = "test_delay_pub_tmp/sub/file.txt";
+  EXPECT_FALSE(file_path_exists_secure(final_path));
+
+  EXPECT_TRUE(delay_updates_publish(cfg->delay_context, cfg));
+  /* After a successful publish the file is installed and staging is gone. */
+  char* content = read_all(final_path);
+  EXPECT_NOT_NULL(content);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (content) {
+    EXPECT_EQ_STR(content, "published payload");
+    free(content);
+  }
+  EXPECT_FALSE(file_path_exists_secure("test_delay_pub_tmp/.fastsync-stage"));
+
+out:
+  file_destroy(f);
+  config_delete(cfg);
+  remove_tree(root);
+}
+
+/* The staged tree is cleaned on the error/abort path and final files that were
+   never published do not appear at the destination. */
+static void test_delay_updates_cleanup_removes_staged() {
+  const char* root = "test_delay_clean_tmp";
+  remove_tree(root);
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->delay_updates = true;
+
+  File* f = make_file("sub/file.txt", "never installed");
+  EXPECT_NOT_NULL(f);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!cfg || !f)
+    goto out;
+
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, cfg), FILE_SAVE_WRITTEN);
+  EXPECT_TRUE(file_path_exists_secure("test_delay_clean_tmp/.fastsync-stage/sub/file.txt"));
+
+  delay_updates_cleanup(cfg->delay_context);
+  EXPECT_FALSE(file_path_exists_secure("test_delay_clean_tmp/.fastsync-stage"));
+  EXPECT_FALSE(file_path_exists_secure("test_delay_clean_tmp/sub/file.txt"));
+
+out:
+  file_destroy(f);
+  config_delete(cfg);
+  remove_tree(root);
+}
+
+/* With --backup the previous version is only moved aside at publication. */
+static void test_delay_updates_backup_deferred_to_publish() {
+  const char* root = "test_delay_bak_tmp";
+  remove_tree(root);
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->delay_updates = true;
+  cfg->backup = true;
+
+  EXPECT_TRUE(file_write_to_disk("test_delay_bak_tmp/file.txt", "AAAA", 4, false, false));
+
+  File* f = make_file("file.txt", "BBBB");
+  EXPECT_NOT_NULL(f);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!cfg || !f)
+    goto out;
+
+  EXPECT_EQ_INT(file_save_to_disk_full(root, f, cfg), FILE_SAVE_WRITTEN);
+  /* Stage time must not touch the final file or create the backup yet. */
+  char* before = read_all("test_delay_bak_tmp/file.txt");
+  EXPECT_NOT_NULL(before);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (before) {
+    EXPECT_EQ_STR(before, "AAAA");
+    free(before);
+  }
+  EXPECT_FALSE(file_path_exists_secure("test_delay_bak_tmp/file.txt~"));
+
+  EXPECT_TRUE(delay_updates_publish(cfg->delay_context, cfg));
+  char* after = read_all("test_delay_bak_tmp/file.txt");
+  char* backup = read_all("test_delay_bak_tmp/file.txt~");
+  EXPECT_NOT_NULL(after);
+  EXPECT_NOT_NULL(backup);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (after) {
+    EXPECT_EQ_STR(after, "BBBB");
+    free(after);
+  }
+  // cppcheck-suppress knownConditionTrueFalse
+  if (backup) {
+    EXPECT_EQ_STR(backup, "AAAA");
+    free(backup);
+  }
+
+out:
+  file_destroy(f);
+  config_delete(cfg);
+  remove_tree(root);
+}
+
+/* Skip/update policy checks run against the final path at stage time, matching
+   what an immediate run would decide. */
+static void test_delay_updates_skip_semantics() {
+  const char* root = "test_delay_skip_tmp";
+  remove_tree(root);
+  Config* cfg = config_create();
+  EXPECT_NOT_NULL(cfg);
+  cfg->delay_updates = true;
+
+  /* --existing: final destination missing -> skipped, nothing staged. */
+  File* missing = make_file("missing.txt", "new");
+  EXPECT_NOT_NULL(missing);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!cfg || !missing)
+    goto out;
+  cfg->existing = true;
+  EXPECT_EQ_INT(file_save_to_disk_full(root, missing, cfg), FILE_SAVE_SKIPPED);
+  cfg->existing = false;
+
+  /* --ignore-existing: final destination present -> skipped. */
+  EXPECT_TRUE(file_write_to_disk("test_delay_skip_tmp/existing.txt", "old", 3, false, false));
+  File* present = make_file("existing.txt", "new");
+  EXPECT_NOT_NULL(present);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!present)
+    goto out;
+  cfg->ignore_existing = true;
+  EXPECT_EQ_INT(file_save_to_disk_full(root, present, cfg), FILE_SAVE_SKIPPED);
+  cfg->ignore_existing = false;
+
+  /* Without a skip flag the file is staged and later published. */
+  File* fresh = make_file("fresh.txt", "content");
+  EXPECT_NOT_NULL(fresh);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (!fresh)
+    goto out;
+  EXPECT_EQ_INT(file_save_to_disk_full(root, fresh, cfg), FILE_SAVE_WRITTEN);
+  EXPECT_TRUE(delay_updates_publish(cfg->delay_context, cfg));
+  char* content = read_all("test_delay_skip_tmp/fresh.txt");
+  EXPECT_NOT_NULL(content);
+  // cppcheck-suppress knownConditionTrueFalse
+  if (content) {
+    EXPECT_EQ_STR(content, "content");
+    free(content);
+  }
+
+out:
+  file_destroy(missing);
+  file_destroy(present);
+  file_destroy(fresh);
+  config_delete(cfg);
+  remove_tree(root);
+}
+
+void test_delay_updates() {
+  test_delay_updates_no_final_before_publish();
+  test_delay_updates_publish_installs_files();
+  test_delay_updates_cleanup_removes_staged();
+  test_delay_updates_backup_deferred_to_publish();
+  test_delay_updates_skip_semantics();
+}