Merge pull request 'Evaluation of codebase by human' (#210) from evaluation-of-codebase-by-human into dev

README.md

@@ -40,12 +40,10 @@ A high-performance file synchronization system with SSH and TCP transport, TLS e
 - Optional progress display with throughput
 - Bandwidth limiting via token-bucket algorithm
 - Configurable I/O and connection timeouts (`--timeout`, `--contimeout`)
-- Quiet mode (`-q`/`--quiet`) suppresses all non-error output
 - Backup overwritten files (`--backup`) with optional directory (`--backup-dir`)
 - Transfer statistics summary (`--stats`)
 - Maximum directory depth control (`--max-depth`)
 - Log file output (`--log-file`)
-- Configurable multithreaded queue size (`--queue-size`)
 - Exclude patterns from file (`--exclude-from`)
 
 ### Server
@@ -116,8 +114,6 @@ Config negotiation is sender-driven: the client serializes transfer options and
 | `-n, --dry-run` | Scan and print what would be transferred |
 | `-p <port>` | SSH port (default: 22) |
 | `-v, --verbose` | Enable debug logging |
-| `-q, --quiet` | Suppress all non-error output |
-| `--silent` | Alias for `--quiet` |
 | `--progress` | Show real-time transfer speed |
 | `--delete` | Delete files on receiver not present in source |
 | `--exclude <pattern>` | Exclude files matching glob pattern (repeatable) |
@@ -135,7 +131,6 @@ Config negotiation is sender-driven: the client serializes transfer options and
 | `--stats` | Print transfer statistics at end (bytes, files, timing) |
 | `--max-depth <n>` | Maximum directory depth to recurse (0 = unlimited, default: 0) |
 | `--log-file <path>` | Write log messages to file instead of stderr |
-| `--queue-size <n>` | Queue capacity for multithreaded mode (default: 100) |
 | `--source-dir <path>` | Source directory (overrides `FASTSYNC_SOURCE_DIR`) |
 | `--dest-dir <path>` | Server destination directory (overrides `FASTSYNC_DEST_DIR`) |
 | `--save-to-disk` | Write received files to disk |
@@ -296,8 +291,8 @@ Place the `fastsync-server` binary in the remote `$PATH`. The client runs `ssh u
 # Bandwidth limit to 1 MB/s
 ./build/client --bwlimit 1024 /src user@host:/dst
 
-# With timeouts, quiet mode, and stats
+# With timeouts and stats
-./build/client --timeout 60 --contimeout 15 --quiet --stats /src user@host:/dst
+./build/client --timeout 60 --contimeout 15 --stats /src user@host:/dst
 
 # Backup overwritten files to a directory
 ./build/client --backup --backup-dir /backups /src user@host:/dst
@@ -305,9 +300,6 @@ Place the `fastsync-server` binary in the remote `$PATH`. The client runs `ssh u
 # Exclude patterns from file, limit depth
 ./build/client --exclude-from ignore.txt --max-depth 3 /src user@host:/dst
 
-# Custom queue size for multithreading
-./build/client -m --queue-size 200 /src user@host:/dst
-
 # Log to file
 ./build/client --log-file /tmp/fastsync.log /src user@host:/dst
 
@@ -334,7 +326,7 @@ The benchmark prints throughput metrics, best configuration, and speedup vs rsyn
 1. Chunk size (~10 MB default) balances memory and transfer efficiency
 2. Compression level trades CPU for bandwidth
 3. `sendfile()` bypasses userspace — ~2× faster on localhost for large files
-4. Multithreading scales with core count; `--queue-size` controls pipeline buffering
+4. Multithreading scales with core count and uses memory-based pipeline sizing
 5. Metadata transfer adds negligible overhead (~24 bytes per file when enabled)
 6. SSH socketpair buffer set to 1 MB for improved pipe throughput
 7. SSH ControlMaster reuses connections across repeated invocations

RSYNC_COMPAT.md

@@ -6,10 +6,10 @@ This document maps rsync's full feature set to FastSync's current implementation
 
 | Status | Count | Description |
 |--------|-------|-------------|
-| ✅ Implemented | 39 | Feature works end-to-end |
+| ✅ Implemented | 34 | Feature works end-to-end |
-| 🔀 Alt Arg | 5 | Functionality exists but under different flag/semantics |
+| 🔀 Alt Arg | 3 | Functionality exists but under different flag/semantics |
-| ⚠️ Partial | 30 | Flag parsed/stored but behavior incomplete |
+| ⚠️ Partial | 1 | Flag parsed/stored but behavior incomplete |
-| ❌ Not Implemented | 62 | Flag not recognized or no behavior |
+| ❌ Not Implemented | 98 | Flag not recognized or no behavior |
 | **Total** | **136** | |
 
 ---
@@ -20,31 +20,31 @@ This document maps rsync's full feature set to FastSync's current implementation
 |------|-------------------|-----------------|-------|
 | `-a`, `--archive` | Archive mode is -rlptgoD | 🔀 Alt Arg | Maps to -c -m -M (compression + multithread + metadata) |
 | `-v`, `--verbose` | Increase verbosity | ✅ Implemented | Sets `log_level=DEBUG` |
-| `-q`, `--quiet` | Suppress non-error messages | ✅ Implemented | `quiet` config field |
+| `-q`, `--quiet` | Suppress non-error messages | ❌ Not Implemented | Removed because it had no effect |
-| `-h`, `--help` | Show help | ✅ Implemented | Prints usage and exits |
+| `--help` | Show help | ✅ Implemented | Prints usage and exits; `-h` is not accepted |
-| `-V`, `--version` | Print version | ❌ Not Implemented | |
+| `-V`, `--version` | Print version | ✅ Implemented | |
-| `--info=FLAGS` | Fine-grained info verbosity | ⚠️ Partial | `info_level` stored, not wired |
+| `--info=FLAGS` | Fine-grained info verbosity | ❌ Not Implemented | Removed because it had no effect |
-| `--debug=FLAGS` | Fine-grained debug verbosity | ⚠️ Partial | `debug_level` stored, not wired |
+| `--debug=FLAGS` | Fine-grained debug verbosity | ❌ Not Implemented | Removed because it had no effect |
 | `--stderr=MODE` | Change stderr output mode | ❌ Not Implemented | |
 | `--no-motd` | Suppress daemon MOTD | ❌ Not Implemented | |
 | `--exclude=PATTERN` | Exclude files matching pattern | ✅ Implemented | Glob matching in scanner |
 | `--include=PATTERN` | Include files matching pattern | ✅ Implemented | Glob matching in scanner |
-| `-C`, `--cvs-exclude` | Auto-ignore CVS files | ⚠️ Partial | `cvs_exclude` stored, not wired |
+| `-C`, `--cvs-exclude` | Auto-ignore CVS files | ❌ Not Implemented | Removed because it had no effect |
 
 ## 2. Modifying Output
 
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
 | `--stats` | Give transfer stats | ✅ Implemented | Prints file/byte counts |
-| `-h`, `--human-readable` | Human-readable numbers | ⚠️ Partial | `human_readable` stored, not wired |
+| `-h`, `--human-readable` | Human-readable numbers | ❌ Not Implemented | Removed because it had no effect |
-| `-i`, `--itemize-changes` | Per-file change summary | ⚠️ Partial | `itemize_changes` stored, not wired |
+| `-i`, `--itemize-changes` | Per-file change summary | ❌ Not Implemented | Removed because it had no effect |
 | `--progress` | Show progress | ✅ Implemented | Progress callback in sender |
 | `-P` | Same as --partial --progress | ❌ Not Implemented | |
-| `--out-format=FORMAT` | Custom output format | ⚠️ Partial | `out_format` stored, not wired |
+| `--out-format=FORMAT` | Custom output format | ❌ Not Implemented | Removed because it had no effect |
 | `--log-file=FILE` | Log to file | ✅ Implemented | `log_file` config field |
 | `--log-file-format=FMT` | Log format | ❌ Not Implemented | |
 | `--8-bit-output` | Leave high-bit chars unescaped | ❌ Not Implemented | |
-| `--list-only` | List files instead of copying | ⚠️ Partial | `list_only` stored, not wired |
+| `--list-only` | List files instead of copying | ❌ Not Implemented | Removed because it had no effect |
 
 ## 3. File Selection
 
@@ -52,8 +52,8 @@ This document maps rsync's full feature set to FastSync's current implementation
 |------|-------------------|-----------------|-------|
 | `--exclude-from=FILE` | Read exclude patterns from file | ✅ Implemented | Reads patterns from file |
 | `--include-from=FILE` | Read include patterns from file | ✅ Implemented | Reads patterns from file |
-| `--filter=RULE` | Add file-filtering rule | ⚠️ Partial | `filters` ArrayList stored, not wired |
+| `--filter=RULE` | Add file-filtering rule | ❌ Not Implemented | Removed because it had no effect |
-| `--files-from=FILE` | Read source file list from file | ⚠️ Partial | `files_from` stored, not wired |
+| `--files-from=FILE` | Read source file list from file | ❌ Not Implemented | Removed because it had no effect |
 | `-0`, `--from0` | Delimit *-from files with NULs | ❌ Not Implemented | |
 | `--max-size=SIZE` | Skip files larger than SIZE | ✅ Implemented | `max_size` in scanner |
 | `--min-size=SIZE` | Skip files smaller than SIZE | ✅ Implemented | `min_size` in scanner |
@@ -69,7 +69,7 @@ This document maps rsync's full feature set to FastSync's current implementation
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
 | `-r`, `--recursive` | Recurse into directories | ✅ Implemented | Default behavior |
-| `-R`, `--relative` | Use relative path names | ⚠️ Partial | `relative` stored, not wired |
+| `-R`, `--relative` | Use relative path names | ❌ Not Implemented | Removed because it had no effect |
 | `--no-implied-dirs` | Don't send implied dirs with -R | ❌ Not Implemented | |
 | `-d`, `--dirs` | Transfer dirs without recursing | ❌ Not Implemented | |
 | `--mkpath` | Create missing path components | ❌ Not Implemented | |
@@ -78,10 +78,10 @@ This document maps rsync's full feature set to FastSync's current implementation
 
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `-u`, `--update` | Skip files newer on receiver | ⚠️ Partial | `update` stored, not wired |
+| `-u`, `--update` | Skip files newer on receiver | ❌ Not Implemented | Removed because it had no effect |
 | `--inplace` | Update files in-place | ✅ Implemented | Direct write mode |
-| `--append` | Append data to shorter files | ⚠️ Partial | `append` stored, not wired |
+| `--append` | Append data to shorter files | ❌ Not Implemented | Removed because it had no effect |
-| `--append-verify` | Append with old-data checksum | ⚠️ Partial | `append_verify` stored, not wired |
+| `--append-verify` | Append with old-data checksum | ❌ Not Implemented | Removed because it had no effect |
 | `-W`, `--whole-file` | Copy whole file (no delta) | ❌ Not Implemented | |
 | `--block-size=SIZE` | Force checksum block-size | ⚠️ Partial | Parsed as `--delta-block`; controls delta transfer block size |
 
@@ -100,15 +100,15 @@ This document maps rsync's full feature set to FastSync's current implementation
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
 | `--delete` | Delete extraneous files from dest | ✅ Implemented | `use_delete` config field |
-| `--delete-before` | Delete before transfer | ⚠️ Partial | `delete_before` stored, not wired |
+| `--delete-before` | Delete before transfer | ❌ Not Implemented | Removed because it had no effect |
 | `--delete-during` | Delete during transfer | ❌ Not Implemented | |
 | `--delete-delay` | Find deletions during, delete after | ❌ Not Implemented | |
-| `--delete-after` | Delete after transfer | ⚠️ Partial | `delete_after` stored, not wired |
+| `--delete-after` | Delete after transfer | ❌ Not Implemented | Removed because it had no effect |
-| `--delete-excluded` | Also delete excluded files | ⚠️ Partial | `delete_excluded` stored, not wired |
+| `--delete-excluded` | Also delete excluded files | ❌ Not Implemented | Removed because it had no effect |
-| `--max-delete=NUM` | Max files to delete | ⚠️ Partial | `max_delete` stored, not wired |
+| `--max-delete=NUM` | Max files to delete | ❌ Not Implemented | Removed because it had no effect |
 | `--ignore-errors` | Delete even with I/O errors | ❌ Not Implemented | |
 | `--force` | Force deletion of non-empty dirs | ❌ Not Implemented | |
-| `--prune-empty-dirs` | Prune empty dir chains | ⚠️ Partial | `prune_empty_dirs` stored, not wired |
+| `--prune-empty-dirs` | Prune empty dir chains | ❌ Not Implemented | Removed because it had no effect |
 
 ## 8. Metadata Preservation
 
@@ -121,11 +121,11 @@ This document maps rsync's full feature set to FastSync's current implementation
 | `-t`, `--times` | Preserve modification times | ✅ Implemented | Part of -M |
 | `-E`, `--executability` | Preserve executability | ❌ Not Implemented | |
 | `--chmod=CHMOD` | Affect file permissions | ❌ Not Implemented | |
-| `-A`, `--acls` | Preserve ACLs | ⚠️ Partial | `preserve_acls` stored, not wired |
+| `-A`, `--acls` | Preserve ACLs | ❌ Not Implemented | Removed because it had no effect |
-| `-X`, `--xattrs` | Preserve extended attributes | ⚠️ Partial | `preserve_xattrs` stored, not wired |
+| `-X`, `--xattrs` | Preserve extended attributes | ❌ Not Implemented | Removed because it had no effect |
-| `-H`, `--hard-links` | Preserve hard links | ⚠️ Partial | `preserve_hard_links` stored, not wired |
+| `-H`, `--hard-links` | Preserve hard links | ❌ Not Implemented | Removed because it had no effect |
-| `-D` | Same as --devices --specials | 🔀 Alt Arg | Maps to --devices only (no --specials) |
+| `-D` | Same as --devices --specials | ❌ Not Implemented | Removed because device-file handling is not implemented |
-| `--devices` | Preserve device files | ⚠️ Partial | `preserve_devices` stored, not wired |
+| `--devices` | Preserve device files | ❌ Not Implemented | Removed because it had no effect |
 | `--specials` | Preserve special files | ❌ Not Implemented | |
 | `--copy-devices` | Copy device contents as file | ❌ Not Implemented | |
 | `--write-devices` | Write to devices as files | ❌ Not Implemented | |
@@ -159,11 +159,11 @@ This document maps rsync's full feature set to FastSync's current implementation
 
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `-c`, `--checksum` | Skip based on checksum | 🔀 Alt Arg | `-c` means compression; `--checksum` stored and forwarded to scanner |
+| `--checksum` | Skip based on checksum | ❌ Not Implemented | Removed because it had no effect; `-c` means compression |
 | `--checksum-choice=STR` | Choose checksum algorithm | ❌ Not Implemented | xxHash used internally |
-| `--compare-dest=DIR` | Compare dest files relative to DIR | ⚠️ Partial | `compare_dest` stored, not wired |
+| `--compare-dest=DIR` | Compare dest files relative to DIR | ❌ Not Implemented | Removed because it had no effect |
-| `--copy-dest=DIR` | Include copies of unchanged files | ⚠️ Partial | `copy_dest` stored, not wired |
+| `--copy-dest=DIR` | Include copies of unchanged files | ❌ Not Implemented | Removed because it had no effect |
-| `--link-dest=DIR` | Hardlink to files when unchanged | ⚠️ Partial | `link_dest` stored, not wired |
+| `--link-dest=DIR` | Hardlink to files when unchanged | ❌ Not Implemented | Removed because it had no effect |
 | `--fuzzy`, `--no-fuzzy` | Find similar file for basis | ❌ Not Implemented | |
 
 ## 12. Compression
@@ -171,7 +171,7 @@ This document maps rsync's full feature set to FastSync's current implementation
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
 | `-z`, `--compress` | Compress file data | 🔀 Alt Arg | Always uses zstd (rsync supports multiple algorithms) |
-| `--compress-choice=STR` | Choose compression algorithm | ⚠️ Partial | `compress_choice` stored, always zstd |
+| `--compress-choice=STR` | Choose compression algorithm | ❌ Not Implemented | Removed because it had no effect; FastSync always uses zstd |
 | `--compress-level=NUM` | Set compression level | ✅ Implemented | 1-22, default 5 |
 | `--compress-threads=NUM` | Set compression threads | ❌ Not Implemented | |
 | `--skip-compress=LIST` | Skip compress for suffixes | ❌ Not Implemented | Internal skip for hardcoded types; not user-configurable |
@@ -180,22 +180,22 @@ This document maps rsync's full feature set to FastSync's current implementation
 
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `-e`, `--rsh=COMMAND` | Remote shell to use | ✅ Implemented | SSH transport support |
+| `-e`, `--rsh=COMMAND` | Remote shell to use | ❌ Not Implemented | Removed; SSH invokes `ssh` directly |
-| `--rsync-path=PROGRAM` | rsync binary on remote | ✅ Implemented | `rsync_path` config field |
+| `--rsync-path=PROGRAM` | rsync binary on remote | ❌ Not Implemented | Removed; use `--fastsync-server-path` |
 | `--port=PORT` | Alternate daemon port | ✅ Implemented | `server_port` config field |
 | `--sockopts=OPTIONS` | Custom TCP options | ❌ Not Implemented | |
 | `--blocking-io` | Use blocking I/O for remote shell | ❌ Not Implemented | |
 | `--outbuf=N\|L\|B` | Set output buffering | ❌ Not Implemented | |
-| `--address=ADDRESS` | Bind address for outgoing socket | ✅ Implemented | `address` config field |
+| `--address=ADDRESS` | Bind address for outgoing socket | ❌ Not Implemented | Removed because it had no effect |
-| `-4`, `--ipv4` | Prefer IPv4 | ✅ Implemented | `ipv4` config field |
+| `-4`, `--ipv4` | Prefer IPv4 | ❌ Not Implemented | Removed because it had no effect |
-| `-6`, `--ipv6` | Prefer IPv6 | ✅ Implemented | `ipv6` config field |
+| `-6`, `--ipv6` | Prefer IPv6 | ❌ Not Implemented | Removed because it had no effect |
 
 ## 14. Daemon Mode
 
 | Flag | Rsync Description | FastSync Status | Notes |
 |------|-------------------|-----------------|-------|
-| `--daemon` | Run as rsync daemon | ⚠️ Partial | `daemon` stored, not wired |
+| `--daemon` | Run as rsync daemon | ❌ Not Implemented | Removed because it had no effect |
-| `--config=FILE` | Alternate rsyncd.conf file | ⚠️ Partial | `daemon_config` stored, not wired |
+| `--config=FILE` | Alternate rsyncd.conf file | ❌ Not Implemented | Removed because it had no effect |
 | `--dparam=OVERRIDE` | Override global daemon config | ❌ Not Implemented | |
 | `--no-detach` | Don't detach from parent | ❌ Not Implemented | |
 | `--password-file=FILE` | Read daemon password from file | ❌ Not Implemented | |
@@ -266,7 +266,6 @@ Ranked by user demand, implementation complexity, and interoperability impact:
 | `-f` / `--sendfile` | Zero-copy sendfile() syscall (TCP only) |
 | `-c [level]` | zstd compression level (1-22) |
 | `--chunk-size` | Configurable chunk size |
-| `--queue-size` | Pipeline queue capacity |
 | `--tls` | TLS encryption (mutual auth) |
 | `--fastsync-server-path` | Path to fastsync-server binary |
 | `--server-host` / `--server-port` | Direct TCP connection |

src/client/client_cli.c

@@ -8,9 +8,11 @@
 #include "utils.h"
 #include <errno.h>
 #include <limits.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include "usage.c"
 
 #ifndef FASTSYNC_TEST_BUILD
 /* Parse environment variables for source/destination directories and save-to-disk flag. */
@@ -25,19 +27,6 @@ static void parse_environment(const char** out_env_source, const char** out_env_
 }
 #endif
 
-/* Parse a string as a positive integer, returning true on success. */
-static bool parse_positive_int(const char* s, int* out_val) {
-  if (!s || *s == '\0')
-    return false;
-  char* endptr;
-  errno = 0;
-  long val = strtol(s, &endptr, 10);
-  if (errno != 0 || *endptr != '\0' || val <= 0 || val > INT_MAX)
-    return false;
-  *out_val = (int)val;
-  return true;
-}
-
 /* Parse a string as a non-negative integer, returning true on success. */
 static bool parse_nonneg_int(const char* s, int* out_val) {
   if (!s || *s == '\0')
@@ -51,7 +40,20 @@ static bool parse_nonneg_int(const char* s, int* out_val) {
   return true;
 }
 
-/* Duplicate a string argument into *dest, freeing the old value. Returns 0 on success, -1 on
+/* Parse a string as a positive integer, returning true on success. */
+static bool parse_positive_int(const char* s, int* out_val) {
+  int temp;
+  if (!parse_nonneg_int(s, &temp)) {
+    return false;
+  }
+  if (temp == 0) {
+    return false;
+  }
+  *out_val = temp;
+  return true;
+}
+
+/* Duplicate a string argument into *dest, freeing the old value. Returns true on success, false on
  * failure. */
 static int set_string_option(char** dest, const char* value, const char* option_name) {
   char* dup = str_dup(value);
@@ -64,7 +66,7 @@ static int set_string_option(char** dest, const char* value, const char* option_
   return 0;
 }
 
-/* Parse a string as a positive integer into *dest. Returns 0 on success, -1 on error. */
+/* Parse a string as a positive integer into *dest. Returns true on success, false on error. */
 static int set_positive_int_option(int* dest, const char* value, const char* option_name) {
   if (!parse_positive_int(value, dest)) {
     fprintf(stderr, "Error: %s must be a positive integer\n", option_name);
@@ -73,7 +75,7 @@ static int set_positive_int_option(int* dest, const char* value, const char* opt
   return 0;
 }
 
-/* Parse a string as a non-negative integer into *dest. Returns 0 on success, -1 on error. */
+/* Parse a string as a non-negative integer into *dest. Returns true on success, false on error. */
 static int set_nonneg_int_option(int* dest, const char* value, const char* option_name) {
   if (!parse_nonneg_int(value, dest)) {
     fprintf(stderr, "Error: %s must be a non-negative integer\n", option_name);
@@ -82,7 +84,6 @@ static int set_nonneg_int_option(int* dest, const char* value, const char* optio
   return 0;
 }
 
-static void print_usage(void);
 static int read_patterns_from_file(const char* filepath, char*** patterns, int* count);
 
 /* Parse CLI arguments into config. Returns 0 on success, -1 on error, 1 for help/clean-exit. */
@@ -103,12 +104,10 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
     } else if (strcmp(argv[i], "-n") == 0 || strcmp(argv[i], "--dry-run") == 0) {
       config->dry_run = true;
     } else if (strcmp(argv[i], "-p") == 0 && i + 1 < argc) {
-      if (!parse_positive_int(argv[++i], &config->ssh_port)) {
+      if (set_positive_int_option(&config->ssh_port, argv[++i], "-p") != 0)
-        fprintf(stderr, "Error: invalid --port/-p value: %s\n", argv[i]);
         return -1;
-      }
       if (config->ssh_port > 65535) {
-        fprintf(stderr, "Error: SSH port must be 1-65535\n");
+        log_message(LOG_LEVEL_ERROR, "SSH port must be 1-65535\n");
         return -1;
       }
     } else if (strcmp(argv[i], "--delete") == 0) {
@@ -275,9 +274,6 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
     } else if (strcmp(argv[i], "--contimeout") == 0 && i + 1 < argc) {
       if (set_positive_int_option(&config->contimeout, argv[++i], "--contimeout") != 0)
         return -1;
-    } else if (strcmp(argv[i], "-q") == 0 || strcmp(argv[i], "--quiet") == 0 ||
-               strcmp(argv[i], "--silent") == 0) {
-      config->quiet = true;
     } else if (strcmp(argv[i], "--backup") == 0) {
       config->backup = true;
     } else if (strcmp(argv[i], "--backup-dir") == 0 && i + 1 < argc) {
@@ -301,9 +297,6 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
       }
       config->log_file = lf;
       log_set_file(lf);
-    } else if (strcmp(argv[i], "--queue-size") == 0 && i + 1 < argc) {
-      if (set_positive_int_option(&config->queue_size, argv[++i], "--queue-size") != 0)
-        return -1;
     } else if (strcmp(argv[i], "--exclude-from") == 0 && i + 1 < argc) {
       if (read_patterns_from_file(argv[++i], &config->exclude_patterns, &config->exclude_count) !=
           0)
@@ -328,126 +321,21 @@ int parse_args(Config* config, int argc, char* argv[], int* positional_args,
       config->safe_links = true;
     } else if (strcmp(argv[i], "--copy-unsafe-links") == 0) {
       config->copy_unsafe_links = true;
-    } else if (strcmp(argv[i], "-H") == 0 || strcmp(argv[i], "--hard-links") == 0) {
-      config->preserve_hard_links = true;
-    } else if (strcmp(argv[i], "-A") == 0 || strcmp(argv[i], "--acls") == 0) {
-      config->preserve_acls = true;
-    } else if (strcmp(argv[i], "-X") == 0 || strcmp(argv[i], "--xattrs") == 0) {
-      config->preserve_xattrs = true;
-    } else if (strcmp(argv[i], "-D") == 0 || strcmp(argv[i], "--devices") == 0) {
-      config->preserve_devices = true;
     } else if (strcmp(argv[i], "-S") == 0 || strcmp(argv[i], "--sparse") == 0) {
       config->preserve_sparse = true;
-    } else if (strcmp(argv[i], "-i") == 0 || strcmp(argv[i], "--itemize-changes") == 0) {
-      config->itemize_changes = true;
-    } else if (strcmp(argv[i], "--out-format") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->out_format, argv[++i], "--out-format") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--info") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->info_level, argv[++i], "--info") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--debug") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->debug_level, argv[++i], "--debug") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--list-only") == 0) {
-      config->list_only = true;
-    } else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--human-readable") == 0) {
-      config->human_readable = true;
-    } else if (strcmp(argv[i], "-u") == 0 || strcmp(argv[i], "--update") == 0) {
-      config->update = true;
     } else if (strcmp(argv[i], "--inplace") == 0) {
       config->inplace = true;
-    } else if (strcmp(argv[i], "--append") == 0) {
-      config->append = true;
-    } else if (strcmp(argv[i], "--append-verify") == 0) {
-      config->append_verify = true;
-    } else if (strcmp(argv[i], "--delete-excluded") == 0) {
-      config->delete_excluded = true;
-    } else if (strcmp(argv[i], "--delete-after") == 0) {
-      config->delete_after = true;
-    } else if (strcmp(argv[i], "--max-delete") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->max_delete, argv[++i], "--max-delete") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--filter") == 0 && i + 1 < argc) {
-      if (!config->filters)
-        config->filters = array_list_create(free);
-      char* dup = str_dup(argv[++i]);
-      if (!dup)
-        return -1;
-      array_list_add(config->filters, dup);
-    } else if (strcmp(argv[i], "--files-from") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->files_from, argv[++i], "--files-from") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--cvs-exclude") == 0) {
-      config->cvs_exclude = true;
-    } else if (strcmp(argv[i], "--prune-empty-dirs") == 0) {
-      config->prune_empty_dirs = true;
-    } else if (strcmp(argv[i], "-R") == 0 || strcmp(argv[i], "--relative") == 0) {
-      config->relative = true;
-    } else if (strcmp(argv[i], "-e") == 0 || strcmp(argv[i], "--rsh") == 0) {
-      if (i + 1 < argc) {
-        if (set_string_option(&config->rsh_command, argv[++i], "-e/--rsh") != 0)
-          return -1;
-      } else {
-        fprintf(stderr, "Error: -e/--rsh requires a command argument\n");
-        return -1;
-      }
-    } else if (strcmp(argv[i], "--rsync-path") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->rsync_path, argv[++i], "--rsync-path") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--temp-dir") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->temp_dir, argv[++i], "--temp-dir") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--compare-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->compare_dest, argv[++i], "--compare-dest") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--copy-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->copy_dest, argv[++i], "--copy-dest") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--link-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->link_dest, argv[++i], "--link-dest") != 0)
-        return -1;
     } else if (strcmp(argv[i], "--partial-dir") == 0 && i + 1 < argc) {
       if (set_string_option(&config->partial_dir, argv[++i], "--partial-dir") != 0)
         return -1;
     } else if (strcmp(argv[i], "--suffix") == 0 && i + 1 < argc) {
       if (set_string_option(&config->suffix, argv[++i], "--suffix") != 0)
         return -1;
-    } else if (strcmp(argv[i], "--delete-before") == 0) {
-      config->delete_before = true;
     } else if (strcmp(argv[i], "-T") == 0 && i + 1 < argc) {
       if (set_positive_int_option(&config->timeout, argv[++i], "-T") != 0)
         return -1;
-    } else if (strcmp(argv[i], "--address") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->address, argv[++i], "--address") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--bind-address") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->bind_address, argv[++i], "--bind-address") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--ipv6") == 0) {
-      config->ipv6 = true;
-    } else if (strcmp(argv[i], "--ipv4") == 0) {
-      config->ipv4 = true;
-    } else if (strcmp(argv[i], "--daemon") == 0) {
-      config->daemon = true;
-    } else if (strcmp(argv[i], "--config") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->daemon_config, argv[++i], "--config") != 0)
-        return -1;
-    } else if (strcmp(argv[i], "--server") == 0) {
-      config->server_mode = true;
     } else if (strcmp(argv[i], "--checksum") == 0) {
       config->checksum = true;
-    } else if (strcmp(argv[i], "--compress-choice") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->compress_choice, argv[++i], "--compress-choice") != 0)
-        return -1;
-      if (strcmp(config->compress_choice, "zstd") == 0)
-        config->use_compression = true;
-      else if (strcmp(config->compress_choice, "none") == 0)
-        config->use_compression = false;
-      else {
-        fprintf(stderr, "Error: --compress-choice must be 'zstd' or 'none'\n");
-        return -1;
-      }
     } else if (strcmp(argv[i], "--compress-level") == 0 && i + 1 < argc) {
       if (set_positive_int_option(&config->compression_level, argv[++i], "--compress-level") != 0)
         return -1;
@@ -521,116 +409,6 @@ static bool validate_config(const Config* config) {
 }
 #endif /* FASTSYNC_TEST_BUILD */
 
-static void print_usage(void) {
-  printf("Usage:\n");
-  printf("  fastsync [options] <source> <destination>\n");
-  printf("  fastsync [options] --source-dir <src> --dest-dir <dst>\n");
-  printf("\n");
-  printf("Destination formats:\n");
-  printf("  user@host:/path     SSH transport (rsync-style)\n");
-  printf("  host:/path          SSH transport (current user)\n");
-  printf("  /local/path         TCP transport (requires server on localhost:8080)\n");
-  printf("\n");
-  printf("Options:\n");
-  printf("  -c [level]          Enable compression (level 1-22, default 5)\n");
-  printf("  -z [level]          Alias for -c\n");
-  printf("  -a, --archive       Archive mode (-c -m -M)\n");
-  printf("  -n, --dry-run       Show what would be transferred\n");
-  printf("  -p <port>           SSH port (default: 22)\n");
-  printf("  --progress          Show transfer progress\n");
-  printf("  --delete            Delete files on receiver not in source\n");
-  printf("  --exclude <pattern> Exclude files matching pattern\n");
-  printf("  --include <pattern> Only include files matching pattern\n");
-  printf("  --exclude-from <file> Read exclude patterns from file\n");
-  printf("  --include-from <file> Read include patterns from file\n");
-  printf("  --max-size <n>      Skip files larger than n bytes\n");
-  printf("  --min-size <n>      Skip files smaller than n bytes\n");
-  printf("  --incremental       Skip files unchanged since last transfer\n");
-  printf("  --delta             Delta transfer for changed files (requires --incremental)\n");
-  printf("  --delta-block <n>   Delta block size in bytes (default: %d)\n",
-         DELTA_BLOCK_SIZE_DEFAULT);
-  printf("  --delta-max <n>     Max file size for delta transfer (default: %llu)\n",
-         DELTA_MAX_FILE_SIZE);
-  printf("  -m                  Enable multithreading\n");
-  printf("  -s                  Enable chunk serialization\n");
-  printf("  -f                  Enable sendfile (TCP only, not with -c or -s)\n");
-  printf("  -v, --verbose       Enable debug logging\n");
-  printf("  -M, --preserve      Preserve file metadata\n");
-  printf("  --chunk-size <n>    Chunk size in bytes (default: %d)\n", DEFAULT_CHUNK_SIZE);
-  printf("  --source-dir <path> Source directory\n");
-  printf("  --dest-dir <path>   Destination directory\n");
-  printf("  --save-to-disk      Write received files to disk\n");
-  printf("  --server-host <ip>  Server IP address (default: 127.0.0.1)\n");
-  printf("  --server-port <n>   Server port (default: 8080)\n");
-  printf("  --bwlimit <KB/s>    Bandwidth limit in kilobytes per second\n");
-  printf("  --tls               Enable TLS encryption\n");
-  printf("  --cert <path>       TLS certificate file (PEM)\n");
-  printf("  --key <path>        TLS private key file (PEM)\n");
-  printf("  --ca <path>         TLS CA certificate file (PEM)\n");
-  printf("  --timeout <sec>     I/O timeout in seconds (default: 30)\n");
-  printf("  -T <sec>            Alias for --timeout\n");
-  printf("  --contimeout <sec>  Connection timeout in seconds (default: 10)\n");
-  printf("  --address <host>    Server hostname/IP to connect to\n");
-  printf("  --bind-address <ip> Bind to specific local address\n");
-  printf("  --ipv6              Prefer IPv6 connections\n");
-  printf("  --ipv4              Prefer IPv4 connections\n");
-  printf("  -q, --quiet         Suppress non-error output\n");
-  printf("  --silent            Alias for --quiet\n");
-  printf("  --backup            Backup existing files before overwriting\n");
-  printf("  --backup-dir <dir>  Directory for backups (requires --backup)\n");
-  printf("  --suffix <str>      Backup suffix (default: ~)\n");
-  printf("  --stats             Print transfer statistics at end\n");
-  printf("  --max-depth <n>     Maximum directory depth (0=unlimited)\n");
-  printf("  --log-file <path>   Write log messages to file\n");
-  printf("  --queue-size <n>    Queue capacity for multithreaded mode (default: 100)\n");
-  printf("  --partial           Keep partial files on interrupted transfer\n");
-  printf("  --partial-dir <dir> Directory for partial files\n");
-  printf("  --fastsync-server-path <path>\n");
-  printf("                      Path to fastsync-server on remote (default: fastsync-server)\n");
-  printf("  -l, --links         Copy symlinks as symlinks\n");
-  printf("  --copy-links        Transform symlinks into referent files\n");
-  printf("  --safe-links        Skip symlinks that point outside transfer tree\n");
-  printf("  --copy-unsafe-links  Only transform unsafe symlinks into referent files\n");
-  printf("  -H, --hard-links    Preserve hard links\n");
-  printf("  -A, --acls          Preserve ACLs\n");
-  printf("  -X, --xattrs        Preserve extended attributes\n");
-  printf("  -D, --devices       Preserve device files\n");
-  printf("  -S, --sparse        Handle sparse files efficiently\n");
-  printf("  -i, --itemize-changes  Show per-file change summary\n");
-  printf("  --out-format <fmt>  Custom output format string\n");
-  printf("  --info <flags>      Info verbosity level\n");
-  printf("  --debug <flags>     Debug verbosity level\n");
-  printf("  --list-only         List files without transferring\n");
-  printf("  -h, --human-readable  Human-readable numbers\n");
-  printf("  -u, --update        Skip files newer on destination\n");
-  printf("  --inplace           Update files in-place (no temp+rename)\n");
-  printf("  --append            Append data to shorter files\n");
-  printf("  --append-verify     Append with verify\n");
-  printf("  --delete-before     Delete before transfer\n");
-  printf("  --delete-excluded   Also delete excluded files\n");
-  printf("  --delete-after      Delete after transfer, not before\n");
-  printf("  --max-delete <n>    Maximum number of files to delete\n");
-  printf("  --filter <rule>     Add file filtering rule\n");
-  printf("  --files-from <file> Read file list from file\n");
-  printf("  --cvs-exclude       Auto-ignore CVS files\n");
-  printf("  --prune-empty-dirs  Omit empty directories from transfer\n");
-  printf("  -R, --relative      Use relative paths\n");
-  printf("  -e, --rsh <cmd>     Specify remote shell\n");
-  printf("  --rsync-path <path> Path to remote binary\n");
-  printf("  --daemon            Run in daemon mode\n");
-  printf("  --config <path>     Path to configuration file\n");
-  printf("  --server            Run in server mode\n");
-  printf("  --checksum          Skip files based on checksum, not mod-time/size\n");
-  printf("  --compress-choice <alg>  Compression algorithm (default: zstd)\n");
-  printf("  --compress-level <n>    Compression level (default: 5)\n");
-  printf("  --temp-dir <dir>    Temporary directory for files\n");
-  printf("  --compare-dest <dir>  Compare destination\n");
-  printf("  --copy-dest <dir>   Copy destination\n");
-  printf("  --link-dest <dir>   Link destination\n");
-  printf("  --help              Show this help\n");
-  printf("  -V, --version       Show version\n");
-}
-
 static int read_patterns_from_file(const char* filepath, char*** patterns, int* count) {
   FILE* fp = fopen(filepath, "r");
   if (!fp) {

src/client/usage.c

@@ -0,0 +1,73 @@
+#include "stdio.h"
+#include <delta.h>
+#include <chunk.h>
+
+static __attribute__((unused)) void print_usage() {
+  printf("Usage:\n");
+  printf("  fastsync [options] <source> <destination>\n");
+  printf("  fastsync [options] --source-dir <src> --dest-dir <dst>\n");
+  printf("\n");
+  printf("Destination formats:\n");
+  printf("  user@host:/path     SSH transport (rsync-style)\n");
+  printf("  host:/path          SSH transport (current user)\n");
+  printf("  /local/path         TCP transport (requires server on localhost:8080)\n");
+  printf("\n");
+  printf("Options:\n");
+  printf("  -c [level]          Enable compression (level 1-22, default 5)\n");
+  printf("  -z [level]          Alias for -c\n");
+  printf("  -a, --archive       Archive mode (-c -m -M)\n");
+  printf("  -n, --dry-run       Show what would be transferred\n");
+  printf("  -p <port>           SSH port (default: 22)\n");
+  printf("  --progress          Show transfer progress\n");
+  printf("  --delete            Delete files on receiver not in source\n");
+  printf("  --exclude <pattern> Exclude files matching pattern\n");
+  printf("  --include <pattern> Only include files matching pattern\n");
+  printf("  --exclude-from <file> Read exclude patterns from file\n");
+  printf("  --include-from <file> Read include patterns from file\n");
+  printf("  --max-size <n>      Skip files larger than n bytes\n");
+  printf("  --min-size <n>      Skip files smaller than n bytes\n");
+  printf("  --incremental       Skip files unchanged since last transfer\n");
+  printf("  --delta             Delta transfer for changed files (requires --incremental)\n");
+  printf("  --delta-block <n>   Delta block size in bytes (default: %d)\n",
+         DELTA_BLOCK_SIZE_DEFAULT);
+  printf("  --delta-max <n>     Max file size for delta transfer (default: %llu)\n",
+         DELTA_MAX_FILE_SIZE);
+  printf("  -m                  Enable multithreading\n");
+  printf("  -s                  Enable chunk serialization\n");
+  printf("  -f                  Enable sendfile (TCP only, not with -c or -s)\n");
+  printf("  -v, --verbose       Enable debug logging\n");
+  printf("  -M, --preserve      Preserve file metadata\n");
+  printf("  --chunk-size <n>    Chunk size in bytes (default: %d)\n", DEFAULT_CHUNK_SIZE);
+  printf("  --source-dir <path> Source directory\n");
+  printf("  --dest-dir <path>   Destination directory\n");
+  printf("  --save-to-disk      Write received files to disk\n");
+  printf("  --server-host <ip>  Server IP address (default: 127.0.0.1)\n");
+  printf("  --server-port <n>   Server port (default: 8080)\n");
+  printf("  --bwlimit <KB/s>    Bandwidth limit in kilobytes per second\n");
+  printf("  --tls               Enable TLS encryption\n");
+  printf("  --cert <path>       TLS certificate file (PEM)\n");
+  printf("  --key <path>        TLS private key file (PEM)\n");
+  printf("  --ca <path>         TLS CA certificate file (PEM)\n");
+  printf("  --timeout <sec>     I/O timeout in seconds (default: 30)\n");
+  printf("  -T <sec>            Alias for --timeout\n");
+  printf("  --contimeout <sec>  Connection timeout in seconds (default: 10)\n");
+  printf("  --backup            Backup existing files before overwriting\n");
+  printf("  --backup-dir <dir>  Directory for backups (requires --backup)\n");
+  printf("  --suffix <str>      Backup suffix (default: ~)\n");
+  printf("  --stats             Print transfer statistics at end\n");
+  printf("  --max-depth <n>     Maximum directory depth (0=unlimited)\n");
+  printf("  --log-file <path>   Write log messages to file\n");
+  printf("  --partial           Keep partial files on interrupted transfer\n");
+  printf("  --partial-dir <dir> Directory for partial files\n");
+  printf("  --fastsync-server-path <path>\n");
+  printf("                      Path to fastsync-server on remote (default: fastsync-server)\n");
+  printf("  -l, --links         Copy symlinks as symlinks\n");
+  printf("  --copy-links        Transform symlinks into referent files\n");
+  printf("  --safe-links        Skip symlinks that point outside transfer tree\n");
+  printf("  --copy-unsafe-links  Only transform unsafe symlinks into referent files\n");
+  printf("  -S, --sparse        Handle sparse files efficiently\n");
+  printf("  --inplace           Update files in-place (no temp+rename)\n");
+  printf("  --compress-level <n>    Compression level (default: 5)\n");
+  printf("  --help              Show this help\n");
+  printf("  -V, --version       Show version\n");
+}

src/shared/log.c

@@ -15,6 +15,15 @@ void log_set_file(FILE* fp) {
   log_fp = fp;
 }
 
+static inline void write_message(FILE* dest_io, LogLevel log_level, struct tm t, const char* format,
+                                 va_list args) {
+  fprintf(dest_io, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t.tm_year + 1900, t.tm_mon + 1,
+          t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec, log_level_strings[log_level]);
+
+  vfprintf(dest_io, format, args);
+  fprintf(dest_io, "\n");
+}
+
 void log_message(LogLevel log_level, const char* format, ...) {
   if (log_level < current_log_level)
     return;
@@ -25,22 +34,19 @@ void log_message(LogLevel log_level, const char* format, ...) {
   if (!localtime_r(&now, &t))
     return;
 
-  fprintf(stderr, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
+  FILE* dest_io = stdout;
-          t.tm_hour, t.tm_min, t.tm_sec, log_level_strings[log_level]);
+  if (log_level == LOG_LEVEL_ERROR) {
+    dest_io = stderr;
+  }
 
   va_list args;
   va_start(args, format);
-  vfprintf(stderr, format, args);
+  write_message(dest_io, log_level, t, format, args);
   va_end(args);
-  fprintf(stderr, "\n");
 
   if (log_fp) {
-    fprintf(log_fp, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t.tm_year + 1900, t.tm_mon + 1,
-            t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec, log_level_strings[log_level]);
     va_start(args, format);
-    vfprintf(log_fp, format, args);
+    write_message(log_fp, log_level, t, format, args);
     va_end(args);
-    fprintf(log_fp, "\n");
-    fflush(log_fp);
   }
 }

tests/test_client_cli.c

@@ -207,6 +207,69 @@ static void test_parse_args_unknown_option() {
   config_delete(cfg);
 }
 
+/* Parsed-but-unimplemented options must fail instead of being silently accepted. */
+static void test_parse_args_rejects_unimplemented_options() {
+  static const char* const options[] = {"-q",
+                                        "--quiet",
+                                        "--silent",
+                                        "--queue-size",
+                                        "-H",
+                                        "--hard-links",
+                                        "-A",
+                                        "--acls",
+                                        "-X",
+                                        "--xattrs",
+                                        "-D",
+                                        "--devices",
+                                        "-i",
+                                        "--itemize-changes",
+                                        "--out-format",
+                                        "--info",
+                                        "--debug",
+                                        "--list-only",
+                                        "-h",
+                                        "--human-readable",
+                                        "-u",
+                                        "--update",
+                                        "--append",
+                                        "--append-verify",
+                                        "--delete-excluded",
+                                        "--delete-after",
+                                        "--max-delete",
+                                        "--filter",
+                                        "--files-from",
+                                        "--cvs-exclude",
+                                        "--prune-empty-dirs",
+                                        "-R",
+                                        "--relative",
+                                        "-e",
+                                        "--rsh",
+                                        "--rsync-path",
+                                        "--temp-dir",
+                                        "--compare-dest",
+                                        "--copy-dest",
+                                        "--link-dest",
+                                        "--delete-before",
+                                        "--address",
+                                        "--bind-address",
+                                        "--ipv6",
+                                        "--ipv4",
+                                        "--daemon",
+                                        "--config",
+                                         "--server",
+                                         "--compress-choice"};
+
+  for (size_t i = 0; i < sizeof(options) / sizeof(options[0]); i++) {
+    Config* cfg = config_create();
+    char* argv[] = {"fastsync", (char*)options[i], "dummy", "/src", "/dst"};
+    int positional_args[2];
+    int positional_count = 0;
+
+    EXPECT_EQ_INT(parse_args(cfg, 5, argv, positional_args, &positional_count), -1);
+    config_delete(cfg);
+  }
+}
+
 /* Test parse_args with --archive flag */
 static void test_parse_args_archive() {
   Config* cfg = config_create();
@@ -238,5 +301,6 @@ void test_client_cli() {
   test_parse_args_invalid_compression_level();
   test_parse_args_valid_compression_level();
   test_parse_args_unknown_option();
+  test_parse_args_rejects_unimplemented_options();
   test_parse_args_archive();
 }