std.Build.Step.WriteFile: extract UpdateSourceFiles

This has been planned for quite some time; this commit finally does it.

Also implements file system watching integration in the make()
implementation for UpdateSourceFiles and fixes the reporting of step
caching for both.

WriteFile does not yet have file system watching integration.

1 files changed, 4 insertions, 85 deletions

diff --git a/lib/std/Build/Step/WriteFile.zig b/lib/std/Build/Step/WriteFile.zig
index 013c58890a..f35bf09b7e 100644
--- a/lib/std/Build/Step/WriteFile.zig
+++ b/lib/std/Build/Step/WriteFile.zig
@@ -1,13 +1,6 @@
-//! WriteFile is primarily used to create a directory in an appropriate
-//! location inside the local cache which has a set of files that have either
-//! been generated during the build, or are copied from the source package.
-//!
-//! However, this step has an additional capability of writing data to paths
-//! relative to the package root, effectively mutating the package's source
-//! files. Be careful with the latter functionality; it should not be used
-//! during the normal build process, but as a utility run by a developer with
-//! intention to update source files, which will then be committed to version
-//! control.
+//! WriteFile is used to create a directory in an appropriate location inside
+//! the local cache which has a set of files that have either been generated
+//! during the build, or are copied from the source package.
 const std = @import("std");
 const Step = std.Build.Step;
 const fs = std.fs;
@@ -19,8 +12,6 @@ step: Step,
 // The elements here are pointers because we need stable pointers for the GeneratedFile field.
 files: std.ArrayListUnmanaged(File),
 directories: std.ArrayListUnmanaged(Directory),
-
-output_source_files: std.ArrayListUnmanaged(OutputSourceFile),
 generated_directory: std.Build.GeneratedFile,
 
 pub const base_id: Step.Id = .write_file;
@@ -52,11 +43,6 @@ pub const Directory = struct {
     };
 };
 
-pub const OutputSourceFile = struct {
-    contents: Contents,
-    sub_path: []const u8,
-};
-
 pub const Contents = union(enum) {
     bytes: []const u8,
     copy: std.Build.LazyPath,
@@ -73,7 +59,6 @@ pub fn create(owner: *std.Build) *WriteFile {
         }),
         .files = .{},
         .directories = .{},
-        .output_source_files = .{},
         .generated_directory = .{ .step = &write_file.step },
     };
     return write_file;
@@ -150,33 +135,6 @@ pub fn addCopyDirectory(
     };
 }
 
-/// A path relative to the package root.
-/// Be careful with this because it updates source files. This should not be
-/// used as part of the normal build process, but as a utility occasionally
-/// run by a developer with intent to modify source files and then commit
-/// those changes to version control.
-pub fn addCopyFileToSource(write_file: *WriteFile, source: std.Build.LazyPath, sub_path: []const u8) void {
-    const b = write_file.step.owner;
-    write_file.output_source_files.append(b.allocator, .{
-        .contents = .{ .copy = source },
-        .sub_path = sub_path,
-    }) catch @panic("OOM");
-    source.addStepDependencies(&write_file.step);
-}
-
-/// A path relative to the package root.
-/// Be careful with this because it updates source files. This should not be
-/// used as part of the normal build process, but as a utility occasionally
-/// run by a developer with intent to modify source files and then commit
-/// those changes to version control.
-pub fn addBytesToSource(write_file: *WriteFile, bytes: []const u8, sub_path: []const u8) void {
-    const b = write_file.step.owner;
-    write_file.output_source_files.append(b.allocator, .{
-        .contents = .{ .bytes = bytes },
-        .sub_path = sub_path,
-    }) catch @panic("OOM");
-}
-
 /// Returns a `LazyPath` representing the base directory that contains all the
 /// files from this `WriteFile`.
 pub fn getDirectory(write_file: *WriteFile) std.Build.LazyPath {
@@ -202,46 +160,6 @@ fn make(step: *Step, prog_node: std.Progress.Node) !void {
     const b = step.owner;
     const write_file: *WriteFile = @fieldParentPtr("step", step);
 
-    // Writing to source files is kind of an extra capability of this
-    // WriteFile - arguably it should be a different step. But anyway here
-    // it is, it happens unconditionally and does not interact with the other
-    // files here.
-    var any_miss = false;
-    for (write_file.output_source_files.items) |output_source_file| {
-        if (fs.path.dirname(output_source_file.sub_path)) |dirname| {
-            b.build_root.handle.makePath(dirname) catch |err| {
-                return step.fail("unable to make path '{}{s}': {s}", .{
-                    b.build_root, dirname, @errorName(err),
-                });
-            };
-        }
-        switch (output_source_file.contents) {
-            .bytes => |bytes| {
-                b.build_root.handle.writeFile(.{ .sub_path = output_source_file.sub_path, .data = bytes }) catch |err| {
-                    return step.fail("unable to write file '{}{s}': {s}", .{
-                        b.build_root, output_source_file.sub_path, @errorName(err),
-                    });
-                };
-                any_miss = true;
-            },
-            .copy => |file_source| {
-                const source_path = file_source.getPath2(b, step);
-                const prev_status = fs.Dir.updateFile(
-                    fs.cwd(),
-                    source_path,
-                    b.build_root.handle,
-                    output_source_file.sub_path,
-                    .{},
-                ) catch |err| {
-                    return step.fail("unable to update file from '{s}' to '{}{s}': {s}", .{
-                        source_path, b.build_root, output_source_file.sub_path, @errorName(err),
-                    });
-                };
-                any_miss = any_miss or prev_status == .stale;
-            },
-        }
-    }
-
     // The cache is used here not really as a way to speed things up - because writing
     // the data to a file would probably be very fast - but as a way to find a canonical
     // location to put build artifacts.
@@ -278,6 +196,7 @@ fn make(step: *Step, prog_node: std.Progress.Node) !void {
     if (try step.cacheHit(&man)) {
         const digest = man.final();
         write_file.generated_directory.path = try b.cache_root.join(b.allocator, &.{ "o", &digest });
+        step.result_cached = true;
         return;
     }