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Transform Plugins

github-actions[bot] edited this page May 23, 2026 · 6 revisions

Transform Plugins

OmegaEdit transform plugins are native shared libraries that can be discovered by the gRPC server and applied to a byte range in a session. They are intended for reusable range operations that should live outside the core editor engine, such as encoding, decoding, compression, checksums, hashes, or binary-safe one-for-one byte transforms.

Plugins are loaded from ordinary platform shared-library files:

Platform Extension
Linux .so
macOS .dylib
Windows .dll

The native ABI is declared in:

  • core/src/include/omega_edit/transform.h
  • core/src/include/omega_edit/transform_plugin_sdk.h

Operation Modes

Each plugin advertises one operation mode:

Mode Behavior
OMEGA_TRANSFORM_PLUGIN_OPERATION_REPLACE Produces replacement bytes for the selected range. Content changes if the selected range or replacement is non-empty.
OMEGA_TRANSFORM_PLUGIN_OPERATION_INSPECT Leaves content unchanged and returns result bytes, such as a checksum or hash.
OMEGA_TRANSFORM_PLUGIN_OPERATION_REPLACE_AND_INSPECT Produces replacement bytes and an inspection result.

Plugins also advertise flags:

Flag Meaning
OMEGA_TRANSFORM_PLUGIN_FLAG_ONE_FOR_ONE Replacement length is expected to match input length.
OMEGA_TRANSFORM_PLUGIN_FLAG_MAY_EXPAND Replacement may be longer than input.
OMEGA_TRANSFORM_PLUGIN_FLAG_MAY_SHRINK Replacement may be shorter than input.
OMEGA_TRANSFORM_PLUGIN_FLAG_TEXT_RESULT Inspection result bytes should be treated as text.
OMEGA_TRANSFORM_PLUGIN_FLAG_BINARY_SAFE Plugin can operate on arbitrary bytes.

Flags are metadata for discovery and user interfaces. The server still validates the actual response it receives from the plugin before applying it.

ABI Contract

A plugin must export two C ABI functions:

OMEGA_TRANSFORM_PLUGIN_EXPORT int
omega_transform_plugin_get_info(omega_transform_plugin_info_t *info_ptr);

OMEGA_TRANSFORM_PLUGIN_EXPORT int
omega_transform_plugin_apply(
    const omega_transform_plugin_request_t *request_ptr,
    omega_transform_plugin_response_t *response_ptr);

omega_transform_plugin_get_info fills out stable metadata:

info_ptr->abi_version = OMEGA_TRANSFORM_PLUGIN_ABI_VERSION;
info_ptr->id = "omega.example.my_plugin";
info_ptr->name = "My Plugin";
info_ptr->description = "What this plugin does.";
info_ptr->operation = OMEGA_TRANSFORM_PLUGIN_OPERATION_REPLACE;
info_ptr->flags = OMEGA_TRANSFORM_PLUGIN_FLAG_BINARY_SAFE;

The plugin ID must be unique across all registered plugins. A reverse-DNS style ID is recommended, for example com.example.base64_encode.

omega_transform_plugin_apply receives:

Field Description
input_bytes / input_length Bytes selected from the current session range.
session_offset Range start offset in the session.
session_length Requested range length after clamping to the session end.
options_json Optional plugin-specific JSON string supplied by the caller.
alloc / allocator_user_data_ptr Allocator that must be used for response-owned memory.

The plugin returns replacement bytes and/or result bytes through omega_transform_plugin_response_t.

Important rules:

  • Return 0 on success and non-zero on failure.
  • Validate null pointers and negative lengths.
  • Allocate all response memory through request_ptr->alloc or the SDK helpers.
  • Do not free response memory yourself after assigning it to the response.
  • Treat options_json as optional; it may be null.
  • Keep plugin entry points thread-safe. The server serializes access to the registry, but plugin code should not rely on mutable global state unless it protects it.

SDK Helpers

Include the SDK header for export macros and allocation helpers:

#include <omega_edit/transform_plugin_sdk.h>

Useful helpers:

Helper Purpose
OMEGA_TRANSFORM_PLUGIN_EXPORT Exports plugin entry points on all supported platforms.
omega_transform_plugin_sdk_alloc Allocates response memory with the server-provided allocator.
omega_transform_plugin_sdk_copy_bytes Copies byte ranges into response-owned memory.
omega_transform_plugin_sdk_copy_cstring Copies C strings into response-owned memory.
omega_transform_plugin_sdk_set_replacement Fills replacement bytes and length.
omega_transform_plugin_sdk_set_text_result Fills text result bytes, label, and MIME type.

Minimal Plugin

This one-for-one example inverts every byte in the selected range:

#include <omega_edit/transform_plugin_sdk.h>

OMEGA_TRANSFORM_PLUGIN_EXPORT int
omega_transform_plugin_get_info(omega_transform_plugin_info_t *info_ptr) {
    if (!info_ptr) return -1;
    info_ptr->abi_version = OMEGA_TRANSFORM_PLUGIN_ABI_VERSION;
    info_ptr->id = "com.example.xor_ff";
    info_ptr->name = "XOR 0xFF";
    info_ptr->description = "Invert every byte in the selected range.";
    info_ptr->operation = OMEGA_TRANSFORM_PLUGIN_OPERATION_REPLACE;
    info_ptr->flags =
        OMEGA_TRANSFORM_PLUGIN_FLAG_ONE_FOR_ONE |
        OMEGA_TRANSFORM_PLUGIN_FLAG_BINARY_SAFE;
    return 0;
}

OMEGA_TRANSFORM_PLUGIN_EXPORT int
omega_transform_plugin_apply(
    const omega_transform_plugin_request_t *request_ptr,
    omega_transform_plugin_response_t *response_ptr) {
    if (!request_ptr || !response_ptr || request_ptr->input_length < 0) {
        return -1;
    }

    omega_byte_t *bytes = omega_transform_plugin_sdk_copy_bytes(
        request_ptr, request_ptr->input_bytes, request_ptr->input_length);
    if (!bytes) return -1;

    for (int64_t i = 0; i < request_ptr->input_length; ++i) {
        bytes[i] = request_ptr->input_bytes[i] ^ 0xff;
    }

    response_ptr->replacement_bytes = bytes;
    response_ptr->replacement_length = request_ptr->input_length;
    return 0;
}

Building Plugins

Plugins are CMake MODULE libraries in this repository. The exemplar plugins are built when either BUILD_EXAMPLES=ON or BUILD_TESTS=ON:

cmake -S . -B _build -DCMAKE_BUILD_TYPE=Release -DBUILD_EXAMPLES=ON
cmake --build _build --config Release --target omega_edit_transform_plugins

The current in-repo output directory is:

_build/packages/core/src/tests/plugins/

The filename does not determine the plugin ID. The plugin ID comes from omega_transform_plugin_get_info.

Plugin Directory Layout

At runtime, put one or more plugin shared libraries in a directory:

plugins/
|- omega_transform_base64_decode.dll
|- omega_transform_base64_encode.dll
|- omega_transform_fnv1a64.dll
|- omega_transform_zlib_compress.dll
|- omega_transform_zlib_decompress.dll
|- omega_transform_xor_ff.dll
|- omega_transform_repeat.dll
`- omega_transform_checksum8.dll

Use the platform extension for your target operating system. Non-plugin files in the directory are ignored if they cannot be loaded or do not expose the required symbols.

Registering Plugins

Native API:

omega_transform_plugin_registry_t *registry =
    omega_transform_plugin_registry_create();

omega_transform_plugin_registry_register_directory(registry, "./plugins");

Native gRPC server CLI:

omega-edit-grpc-server --port=9000 --transform-plugin-dir ./plugins

The flag can be repeated. The server also reads a platform-path-list environment variable:

OMEGA_EDIT_TRANSFORM_PLUGIN_DIRS="./plugins:./more-plugins"

On Windows, use semicolons:

$env:OMEGA_EDIT_TRANSFORM_PLUGIN_DIRS = ".\plugins;.\more-plugins"

TypeScript server launcher:

import { runServer } from '@omega-edit/server'

await runServer(9000, '127.0.0.1', undefined, {
  transformPluginDirectories: ['./plugins'],
})

Discovering and Applying Plugins

TypeScript client:

import {
  applyTransformPlugin,
  createSession,
  listTransformPlugins,
  startServer,
} from '@omega-edit/client'

await startServer(9000, '127.0.0.1', undefined, {
  transformPluginDirectories: ['./plugins'],
})

const plugins = await listTransformPlugins()
console.log(plugins.map((plugin) => plugin.id))

const sessionId = (await createSession('input.bin')).getSessionId()
const result = await applyTransformPlugin(
  sessionId,
  'omega.example.checksum8',
  0,
  1024
)
console.log(Buffer.from(result.result).toString('utf8'))

AI CLI:

oe list-transform-plugins
oe apply-transform-plugin \
  --session <session-id> \
  --plugin omega.example.checksum8 \
  --offset 0 \
  --length 1024
oe apply-transform-plugin \
  --session <session-id> \
  --plugin omega.example.base64_encode \
  --offset 0 \
  --length 1024
oe apply-transform-plugin \
  --session <session-id> \
  --plugin omega.example.zlib_compress \
  --offset 0 \
  --length 1024

MCP tools:

  • omega_edit_list_transform_plugins
  • omega_edit_apply_transform_plugin

Exemplar Plugins

The repository ships small examples in core/src/plugins/:

Plugin ID Source Operation Demonstrates
omega.example.base64_encode base64_encode.c Replace Expansion by encoding arbitrary bytes as base64 text.
omega.example.base64_decode base64_decode.c Replace Shrinking text content back to decoded bytes, with validation. ASCII whitespace is tolerated; other invalid bytes fail.
omega.example.fnv1a64 fnv1a64.c Inspect 64-bit hash calculation without changing session content.
omega.example.zlib_compress zlib_compress.c Replace Valid zlib streams using stored DEFLATE blocks, without a required external dependency.
omega.example.zlib_decompress zlib_decompress.c Replace Shrinking stored-block zlib streams back to the original bytes, with header and checksum validation.
omega.example.xor_ff xor_ff.c Replace One-for-one binary-safe byte transform.
omega.example.repeat repeat.c Replace Expansion by replacing a range with two copies of itself.
omega.example.checksum8 checksum8.c Inspect Text result without changing session content.

These examples are intentionally small so they can serve as test fixtures and copyable developer starting points.

The zlib examples intentionally avoid a required external compression dependency: omega.example.zlib_compress emits valid zlib streams with stored DEFLATE blocks, and omega.example.zlib_decompress accepts that stored-block subset with zlib header and Adler-32 validation. Because stored blocks have no compression level, the exemplar compressor intentionally ignores options_json; a production compression plugin can use that field for settings such as compression level.

Release Notes for Plugin Authors

The current ABI version is 1.

When changing the ABI:

  1. Bump OMEGA_TRANSFORM_PLUGIN_ABI_VERSION.
  2. Keep the server's load-time ABI validation strict.
  3. Update this page and the exemplar plugins.
  4. Mention the ABI version change in release notes.

When adding release plugins:

  1. Put source under core/src/plugins/.
  2. Add the source file to the plugin target list in core/CMakeLists.txt.
  3. Add native registry/harness coverage.
  4. Add client or AI coverage if the plugin exercises new behavior.
  5. Document the plugin ID, operation, options JSON, and result format.

See Also

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