feat: allow client to specify sha256 values and generate an assets declaration (#92)

- Declare the toolchains in a separate repository.
- Rename `assets` to `prebuilt_assets`.
- Refactor `assets.create()` to be tool agnostic.

Closes #87.

Author: cgrindel

WORKSPACE

@@ -2,14 +2,11 @@ workspace(name = "cgrindel_rules_swiftformat")
 
 load(
     "//swiftformat:deps.bzl",
-    "swiftformat_register_toolchains",
     "swiftformat_rules_dependencies",
 )
 
 swiftformat_rules_dependencies()
 
-swiftformat_register_toolchains(version = "0.51.10")
-
 load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
 
 bazel_skylib_workspace()

examples/exclude_files/WORKSPACE

@@ -7,14 +7,11 @@ local_repository(
 
 load(
     "@cgrindel_rules_swiftformat//swiftformat:deps.bzl",
-    "swiftformat_register_toolchains",
     "swiftformat_rules_dependencies",
 )
 
 swiftformat_rules_dependencies()
 
-swiftformat_register_toolchains(version = "0.51.10")
-
 load(
     "@cgrindel_bazel_starlib//:deps.bzl",
     "bazel_starlib_dependencies",
@@ -35,3 +32,10 @@ load(
 )
 
 swift_rules_extra_dependencies()
+
+load(
+    "@cgrindel_rules_swiftformat//swiftformat:defs.bzl",
+    "swiftformat_register_prebuilt_toolchains",
+)
+
+swiftformat_register_prebuilt_toolchains()

examples/rules_swift_helpers/WORKSPACE

@@ -7,14 +7,11 @@ local_repository(
 
 load(
     "@cgrindel_rules_swiftformat//swiftformat:deps.bzl",
-    "swiftformat_register_toolchains",
     "swiftformat_rules_dependencies",
 )
 
 swiftformat_rules_dependencies()
 
-swiftformat_register_toolchains(version = "0.51.10")
-
 load(
     "@cgrindel_bazel_starlib//:deps.bzl",
     "bazel_starlib_dependencies",
@@ -35,3 +32,10 @@ load(
 )
 
 swift_rules_extra_dependencies()
+
+load(
+    "@cgrindel_rules_swiftformat//swiftformat:defs.bzl",
+    "swiftformat_register_prebuilt_toolchains",
+)
+
+swiftformat_register_prebuilt_toolchains()

examples/simple/WORKSPACE

@@ -7,13 +7,14 @@ local_repository(
 
 load(
     "@cgrindel_rules_swiftformat//swiftformat:deps.bzl",
-    "swiftformat_register_toolchains",
     "swiftformat_rules_dependencies",
 )
 
 swiftformat_rules_dependencies()
 
-swiftformat_register_toolchains(version = "0.51.10")
+load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+
+bazel_skylib_workspace()
 
 load(
     "@cgrindel_bazel_starlib//:deps.bzl",
@@ -35,3 +36,10 @@ load(
 )
 
 swift_rules_extra_dependencies()
+
+load(
+    "@cgrindel_rules_swiftformat//swiftformat:defs.bzl",
+    "swiftformat_register_prebuilt_toolchains",
+)
+
+swiftformat_register_prebuilt_toolchains()

swiftformat/BUILD.bazel

@@ -19,6 +19,7 @@ bzl_library(
         "//swiftformat/internal:swiftformat_library",
         "//swiftformat/internal:swiftformat_pkg",
         "//swiftformat/internal:swiftformat_test",
+        "//swiftformat/toolchains:toolchain",
     ],
 )
 
@@ -42,7 +43,6 @@ bzl_library(
     name = "deps",
     srcs = ["deps.bzl"],
     deps = [
-        "//swiftformat/toolchains:assets",
         "@bazel_tools//tools/build_defs/repo:http.bzl",
         "@bazel_tools//tools/build_defs/repo:utils.bzl",
     ],

swiftformat/defs.bzl

@@ -24,6 +24,13 @@ load(
     "//swiftformat/internal:swiftformat_test.bzl",
     _swiftformat_test = "swiftformat_test",
 )
+load(
+    "//swiftformat/toolchains:toolchain.bzl",
+    _swiftformat_register_prebuilt_toolchains = "swiftformat_register_prebuilt_toolchains",
+)
+
+# Toolchain Registration
+swiftformat_register_prebuilt_toolchains = _swiftformat_register_prebuilt_toolchains
 
 # Macros
 swiftformat_pkg = _swiftformat_pkg

swiftformat/deps.bzl

@@ -2,12 +2,6 @@
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
-load(
-    "//swiftformat/toolchains:assets.bzl",
-    _swiftformat_register_toolchains = "swiftformat_register_toolchains",
-)
-
-swiftformat_register_toolchains = _swiftformat_register_toolchains
 
 def swiftformat_rules_dependencies():
     """Loads the dependencies for `rules_swiftformat`."""

swiftformat/toolchains/BUILD.bazel

@@ -1,6 +1,5 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load("@cgrindel_bazel_starlib//bzlformat:defs.bzl", "bzlformat_pkg")
-load(":toolchain.bzl", "declare_swiftformat_toolchains")
 
 bzlformat_pkg(name = "bzlformat")
 
@@ -10,20 +9,23 @@ filegroup(
     visibility = ["//:__subpackages__"],
 )
 
-# Toolchain
-
-declare_swiftformat_toolchains()
-
 bzl_library(
-    name = "assets",
-    srcs = ["assets.bzl"],
+    name = "prebuilt_assets",
+    srcs = ["prebuilt_assets.bzl"],
     visibility = ["//visibility:public"],
-    deps = ["@bazel_tools//tools/build_defs/repo:http.bzl"],
+    deps = [
+        "@bazel_skylib//lib:types",
+        "@bazel_tools//tools/build_defs/repo:http.bzl",
+    ],
 )
 
 bzl_library(
     name = "toolchain",
     srcs = ["toolchain.bzl"],
     visibility = ["//visibility:public"],
-    deps = [":assets"],
+    deps = [
+        ":prebuilt_assets",
+        "@bazel_tools//tools/build_defs/repo:http.bzl",
+        "@bazel_tools//tools/build_defs/repo:utils.bzl",
+    ],
 )

swiftformat/toolchains/assets.bzl

@@ -0,0 +1,110 @@
+"""Support downloading prebuilt SwiftFormat binaries."""
+
+load("@bazel_skylib//lib:types.bzl", "types")
+
+# _VALID_TOOLS = ["swiftformat"]
+
+def _create(
+        os,
+        cpu,
+        file,
+        urls,
+        executable_label,
+        repo,
+        sha256 = None,
+        swiftformat_toolchain_name = None,
+        toolchain_name = None):
+    """Create an asset.
+
+    Args:
+        os: The operating system name as a `string`.
+        cpu: The cpu as a `string`.
+        file: The name of the executable in the archive as a `string`.
+        urls: A `list` of urls to download the archive file that contains the
+            executable.
+        executable_label: The label for the executable as a `string`.
+        repo: The name of the repository for the downloaded archive as a
+            `string`.
+        sha256: Optional. The SHA256 value for the archive as a `string`.
+        swiftformat_toolchain_name: Optional. The name for the
+            `swiftformat_toolchain` as a `string`.
+        toolchain_name: Optional. The name of the `toolchain` as a `string`.
+
+    Returns:
+        A `struct` representing a downloadable asset.
+    """
+    if swiftformat_toolchain_name == None:
+        swiftformat_toolchain_name = repo
+    if toolchain_name == None:
+        toolchain_name = swiftformat_toolchain_name + "_toolchain"
+    return struct(
+        os = os,
+        cpu = cpu,
+        file = file,
+        urls = urls,
+        repo = repo,
+        swiftformat_toolchain_name = swiftformat_toolchain_name,
+        toolchain_name = toolchain_name,
+        executable_label = executable_label,
+        sha256 = sha256,
+    )
+
+_SWIFTFORMAT_DOWNLOAD_URL_TEMPLATE = """\
+https://github.com/nicklockwood/SwiftFormat/releases/download/{version}/{archive}\
+"""
+
+def _create_swiftformat(version, os, cpu, file, sha256 = None):
+    """Create an asset declaration for the swiftformat tool.
+
+    Args:
+        version: The version as a `string`.
+        os: The operating system name as a `string`.
+        cpu: The cpu as a `string`.
+        file: The name of the executable in the archive as a `string`.
+        sha256: Optional. The SHA256 value for the archive file as a `string`.
+
+    Returns:
+        An asset `struct` as returned by `prebuilt_assets.create()`.
+    """
+    repo = "swiftformat_download_{os}_{cpu}".format(
+        os = os,
+        cpu = cpu,
+    )
+    archive = file + ".zip"
+    return _create(
+        os = os,
+        cpu = cpu,
+        file = file,
+        urls = [
+            _SWIFTFORMAT_DOWNLOAD_URL_TEMPLATE.format(
+                version = version,
+                archive = archive,
+            ),
+        ],
+        executable_label = "@{repo}//:executable".format(repo = repo),
+        repo = repo,
+        sha256 = sha256,
+    )
+
+def _from_json(json_str):
+    """Returns an asset `struct` or a `list` of asset `struct` values as \
+    represented by the JSON `string`.
+
+    Args:
+        json_str: A JSON `string` representing an asset or a list of assets.
+
+    Returns:
+        An asset `struct` or a `list` of asset `struct` values.
+    """
+    result = json.decode(json_str)
+    if types.is_list(result):
+        return [_create(**a) for a in result]
+    elif types.is_dict(result):
+        return _create(**result)
+    fail("Unexpected result type decoding JSON string. %s" % (json_str))
+
+prebuilt_assets = struct(
+    create = _create,
+    create_swiftformat = _create_swiftformat,
+    from_json = _from_json,
+)