Add FreeBSD platform support

Package.swift

@@ -43,6 +43,7 @@ let package = Package(
                 .target(name: "SwiftlyCore"),
                 .target(name: "LinuxPlatform", condition: .when(platforms: [.linux])),
                 .target(name: "MacOSPlatform", condition: .when(platforms: [.macOS])),
+                .target(name: "FreeBSDPlatform", condition: .when(platforms: [.custom("freebsd")])),
                 .product(name: "SwiftToolsSupport-auto", package: "swift-tools-support-core"),
                 .product(name: "SystemPackage", package: "swift-system"),
             ],
@@ -55,6 +56,7 @@ let package = Package(
                 .target(name: "SwiftlyCore"),
                 .target(name: "LinuxPlatform", condition: .when(platforms: [.linux])),
                 .target(name: "MacOSPlatform", condition: .when(platforms: [.macOS])),
+                .target(name: "FreeBSDPlatform", condition: .when(platforms: [.custom("freebsd")])),
             ],
             swiftSettings: swiftSettings
         ),
@@ -138,6 +140,7 @@ let package = Package(
                 .target(name: "SwiftlyCore"),
                 .target(name: "LinuxPlatform", condition: .when(platforms: [.linux])),
                 .target(name: "MacOSPlatform", condition: .when(platforms: [.macOS])),
+                .target(name: "FreeBSDPlatform", condition: .when(platforms: [.custom("freebsd")])),
                 .product(name: "ArgumentParser", package: "swift-argument-parser"),
                 .product(name: "_NIOFileSystem", package: "swift-nio"),
             ],
@@ -164,6 +167,18 @@ let package = Package(
             ],
             swiftSettings: swiftSettings
         ),
+        .target(
+            name: "FreeBSDPlatform",
+            dependencies: [
+                "SwiftlyCore",
+                "CLibArchive",
+                .product(name: "SystemPackage", package: "swift-system"),
+            ],
+            swiftSettings: swiftSettings,
+            linkerSettings: [
+                .linkedLibrary("z"),
+            ]
+        ),
         .systemLibrary(
             name: "CLibArchive",
             pkgConfig: "libarchive",

Sources/FreeBSDPlatform/Extract.swift

@@ -0,0 +1,104 @@
+#if os(FreeBSD)
+import CLibArchive
+import Foundation
+import SystemPackage
+
+// The code in this file consists mainly of a Swift port of the "Complete Extractor" example included in the libarchive
+// documentation: https://github.com/libarchive/libarchive/wiki/Examples#a-complete-extractor
+
+struct ExtractError: Error {
+    let message: String?
+
+    init(archive: OpaquePointer?) {
+        self.message = archive_error_string(archive).map { err in
+            String(cString: err)
+        }
+    }
+
+    init(message: String) {
+        self.message = message
+    }
+}
+
+/// Write the data from the given readArchive into the writeArchive.
+func copyData(readArchive: OpaquePointer?, writeArchive: OpaquePointer?) throws {
+    var r = 0
+    var buff: UnsafeRawPointer?
+    var size = 0
+    var offset: Int64 = 0
+
+    while true {
+        r = Int(archive_read_data_block(readArchive, &buff, &size, &offset))
+        if r == ARCHIVE_EOF {
+            return
+        }
+        guard r == ARCHIVE_OK else {
+            throw ExtractError(archive: readArchive)
+        }
+        r = Int(archive_write_data_block(writeArchive, buff, size, offset))
+        guard r == ARCHIVE_OK else {
+            throw ExtractError(archive: writeArchive)
+        }
+    }
+}
+
+/// Extract the archive at the provided path. The name of each file included in the archive will be passed to
+/// the provided closure which will return the path the file will be written to.
+///
+/// This uses libarchive under the hood, so a wide variety of archive formats are supported (e.g. .tar.gz).
+func extractArchive(atPath archivePath: FilePath, transform: (String) -> FilePath) throws {
+    var flags = Int32(0)
+    flags = ARCHIVE_EXTRACT_TIME
+    flags |= ARCHIVE_EXTRACT_PERM
+    flags |= ARCHIVE_EXTRACT_ACL
+    flags |= ARCHIVE_EXTRACT_FFLAGS
+
+    let a = archive_read_new()
+    archive_read_support_format_all(a)
+    archive_read_support_filter_all(a)
+
+    let ext = archive_write_disk_new()
+    archive_write_disk_set_options(ext, flags)
+    archive_write_disk_set_standard_lookup(ext)
+
+    defer {
+        archive_read_close(a)
+        archive_read_free(a)
+        archive_write_close(ext)
+        archive_write_free(ext)
+    }
+
+    if archive_read_open_filename(a, archivePath.string, 10240) != 0 {
+        throw ExtractError(message: "Failed to open \"\(archivePath)\"")
+    }
+
+    while true {
+        var r = Int32(0)
+        var entry: OpaquePointer?
+        r = archive_read_next_header(a, &entry)
+        if r == ARCHIVE_EOF {
+            break
+        }
+        guard r == ARCHIVE_OK else {
+            throw ExtractError(archive: a)
+        }
+
+        let currentPath = String(cString: archive_entry_pathname(entry))
+        archive_entry_set_pathname(entry, transform(currentPath).string)
+        r = archive_write_header(ext, entry)
+        guard r == ARCHIVE_OK else {
+            throw ExtractError(archive: ext)
+        }
+
+        if archive_entry_size(entry) > 0 {
+            try copyData(readArchive: a, writeArchive: ext)
+        }
+
+        r = archive_write_finish_entry(ext)
+        guard r == ARCHIVE_OK else {
+            throw ExtractError(archive: ext)
+        }
+    }
+}
+
+#endif