Merge pull request #14562: std.Build: enhancements to ConfigHeaderStep

lib/std/Build.zig

@@ -598,13 +598,17 @@ pub fn addSystemCommand(self: *Build, argv: []const []const u8) *RunStep {
     return run_step;
 }
 
+/// Using the `values` provided, produces a C header file, possibly based on a
+/// template input file (e.g. config.h.in).
+/// When an input template file is provided, this function will fail the build
+/// when an option not found in the input file is provided in `values`, and
+/// when an option found in the input file is missing from `values`.
 pub fn addConfigHeader(
     b: *Build,
-    source: FileSource,
+    options: ConfigHeaderStep.Options,
-    style: ConfigHeaderStep.Style,
     values: anytype,
 ) *ConfigHeaderStep {
-    const config_header_step = ConfigHeaderStep.create(b, source, style);
+    const config_header_step = ConfigHeaderStep.create(b, options);
     config_header_step.addValues(values);
     return config_header_step;
 }

lib/std/Build/CompileStep.zig

@@ -442,6 +442,26 @@ pub fn installHeader(a: *CompileStep, src_path: []const u8, dest_rel_path: []con
     a.installed_headers.append(&install_file.step) catch @panic("OOM");
 }
 
+pub const InstallConfigHeaderOptions = struct {
+    install_dir: InstallDir = .header,
+    dest_rel_path: ?[]const u8 = null,
+};
+
+pub fn installConfigHeader(
+    cs: *CompileStep,
+    config_header: *ConfigHeaderStep,
+    options: InstallConfigHeaderOptions,
+) void {
+    const dest_rel_path = options.dest_rel_path orelse config_header.include_path;
+    const install_file = cs.builder.addInstallFileWithDir(
+        .{ .generated = &config_header.output_file },
+        options.install_dir,
+        dest_rel_path,
+    );
+    cs.builder.getInstallStep().dependOn(&install_file.step);
+    cs.installed_headers.append(&install_file.step) catch @panic("OOM");
+}
+
 pub fn installHeadersDirectory(
     a: *CompileStep,
     src_dir_path: []const u8,
@@ -1622,8 +1642,9 @@ fn make(step: *Step) !void {
                 }
             },
             .config_header_step => |config_header| {
-                try zig_args.append("-I");
+                const full_file_path = config_header.output_file.path.?;
-                try zig_args.append(config_header.output_dir);
+                const header_dir_path = full_file_path[0 .. full_file_path.len - config_header.include_path.len];
+                try zig_args.appendSlice(&.{ "-I", header_dir_path });
             },
         }
     }

lib/std/Build/ConfigHeaderStep.zig

@@ -4,13 +4,22 @@ const Step = std.Build.Step;
 
 pub const base_id: Step.Id = .config_header;
 
-pub const Style = enum {
+pub const Style = union(enum) {
     /// The configure format supported by autotools. It uses `#undef foo` to
     /// mark lines that can be substituted with different values.
-    autoconf,
+    autoconf: std.Build.FileSource,
     /// The configure format supported by CMake. It uses `@@FOO@@` and
     /// `#cmakedefine` for template substitution.
-    cmake,
+    cmake: std.Build.FileSource,
+    /// Instead of starting with an input file, start with nothing.
+    blank,
+
+    pub fn getFileSource(style: Style) ?std.Build.FileSource {
+        switch (style) {
+            .autoconf, .cmake => |s| return s,
+            .blank => return null,
+        }
+    }
 };
 
 pub const Value = union(enum) {
@@ -24,34 +33,50 @@ pub const Value = union(enum) {
 
 step: Step,
 builder: *std.Build,
-source: std.Build.FileSource,
+values: std.StringArrayHashMap(Value),
-style: Style,
+output_file: std.Build.GeneratedFile,
-values: std.StringHashMap(Value),
-max_bytes: usize = 2 * 1024 * 1024,
-output_dir: []const u8,
-output_basename: []const u8,
 
-pub fn create(builder: *std.Build, source: std.Build.FileSource, style: Style) *ConfigHeaderStep {
+style: Style,
+max_bytes: usize,
+include_path: []const u8,
+
+pub const Options = struct {
+    style: Style = .blank,
+    max_bytes: usize = 2 * 1024 * 1024,
+    include_path: ?[]const u8 = null,
+};
+
+pub fn create(builder: *std.Build, options: Options) *ConfigHeaderStep {
     const self = builder.allocator.create(ConfigHeaderStep) catch @panic("OOM");
-    const name = builder.fmt("configure header {s}", .{source.getDisplayName()});
+    const name = if (options.style.getFileSource()) |s|
+        builder.fmt("configure {s} header {s}", .{ @tagName(options.style), s.getDisplayName() })
+    else
+        builder.fmt("configure {s} header", .{@tagName(options.style)});
     self.* = .{
         .builder = builder,
         .step = Step.init(base_id, name, builder.allocator, make),
-        .source = source,
+        .style = options.style,
-        .style = style,
+        .values = std.StringArrayHashMap(Value).init(builder.allocator),
-        .values = std.StringHashMap(Value).init(builder.allocator),
+
-        .output_dir = undefined,
+        .max_bytes = options.max_bytes,
-        .output_basename = "config.h",
+        .include_path = "config.h",
+        .output_file = .{ .step = &self.step },
     };
-    switch (source) {
+
+    if (options.style.getFileSource()) |s| switch (s) {
         .path => |p| {
             const basename = std.fs.path.basename(p);
             if (std.mem.endsWith(u8, basename, ".h.in")) {
-                self.output_basename = basename[0 .. basename.len - 3];
+                self.include_path = basename[0 .. basename.len - 3];
             }
         },
         else => {},
+    };
+
+    if (options.include_path) |include_path| {
+        self.include_path = include_path;
     }
+
     return self;
 }
 
@@ -112,8 +137,6 @@ fn putValue(self: *ConfigHeaderStep, field_name: []const u8, comptime T: type, v
 fn make(step: *Step) !void {
     const self = @fieldParentPtr(ConfigHeaderStep, "step", step);
     const gpa = self.builder.allocator;
-    const src_path = self.source.getPath(self.builder);
-    const contents = try std.fs.cwd().readFileAlloc(gpa, src_path, self.max_bytes);
 
     // 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
@@ -130,9 +153,30 @@ fn make(step: *Step) !void {
     // Random bytes to make ConfigHeaderStep unique. Refresh this with new
     // random bytes when ConfigHeaderStep implementation is modified in a
     // non-backwards-compatible way.
-    var hash = Hasher.init("X1pQzdDt91Zlh7Eh");
+    var hash = Hasher.init("PGuDTpidxyMqnkGM");
-    hash.update(self.source.getDisplayName());
+
-    hash.update(contents);
+    var output = std.ArrayList(u8).init(gpa);
+    defer output.deinit();
+
+    try output.appendSlice("/* This file was generated by ConfigHeaderStep using the Zig Build System. */\n");
+
+    switch (self.style) {
+        .autoconf => |file_source| {
+            const src_path = file_source.getPath(self.builder);
+            const contents = try std.fs.cwd().readFileAlloc(gpa, src_path, self.max_bytes);
+            try render_autoconf(contents, &output, self.values, src_path);
+        },
+        .cmake => |file_source| {
+            const src_path = file_source.getPath(self.builder);
+            const contents = try std.fs.cwd().readFileAlloc(gpa, src_path, self.max_bytes);
+            try render_cmake(contents, &output, self.values, src_path);
+        },
+        .blank => {
+            try render_blank(&output, self.values, self.include_path);
+        },
+    }
+
+    hash.update(output.items);
 
     var digest: [16]u8 = undefined;
     hash.final(&digest);
@@ -143,38 +187,42 @@ fn make(step: *Step) !void {
         .{std.fmt.fmtSliceHexLower(&digest)},
     ) catch unreachable;
 
-    self.output_dir = try std.fs.path.join(gpa, &[_][]const u8{
+    const output_dir = try std.fs.path.join(gpa, &[_][]const u8{
         self.builder.cache_root, "o", &hash_basename,
     });
-    var dir = std.fs.cwd().makeOpenPath(self.output_dir, .{}) catch |err| {
+
-        std.debug.print("unable to make path {s}: {s}\n", .{ self.output_dir, @errorName(err) });
+    // If output_path has directory parts, deal with them.  Example:
+    // output_dir is zig-cache/o/HASH
+    // output_path is libavutil/avconfig.h
+    // We want to open directory zig-cache/o/HASH/libavutil/
+    // but keep output_dir as zig-cache/o/HASH for -I include
+    const sub_dir_path = if (std.fs.path.dirname(self.include_path)) |d|
+        try std.fs.path.join(gpa, &.{ output_dir, d })
+    else
+        output_dir;
+
+    var dir = std.fs.cwd().makeOpenPath(sub_dir_path, .{}) catch |err| {
+        std.debug.print("unable to make path {s}: {s}\n", .{ output_dir, @errorName(err) });
         return err;
     };
     defer dir.close();
 
-    var values_copy = try self.values.clone();
+    try dir.writeFile(std.fs.path.basename(self.include_path), output.items);
-    defer values_copy.deinit();
 
-    var output = std.ArrayList(u8).init(gpa);
+    self.output_file.path = try std.fs.path.join(self.builder.allocator, &.{
-    defer output.deinit();
+        output_dir, self.include_path,
-    try output.ensureTotalCapacity(contents.len);
+    });
-
-    try output.appendSlice("/* This file was generated by ConfigHeaderStep using the Zig Build System. */\n");
-
-    switch (self.style) {
-        .autoconf => try render_autoconf(contents, &output, &values_copy, src_path),
-        .cmake => try render_cmake(contents, &output, &values_copy, src_path),
-    }
-
-    try dir.writeFile(self.output_basename, output.items);
 }
 
 fn render_autoconf(
     contents: []const u8,
     output: *std.ArrayList(u8),
-    values_copy: *std.StringHashMap(Value),
+    values: std.StringArrayHashMap(Value),
     src_path: []const u8,
 ) !void {
+    var values_copy = try values.clone();
+    defer values_copy.deinit();
+
     var any_errors = false;
     var line_index: u32 = 0;
     var line_it = std.mem.split(u8, contents, "\n");
@@ -192,7 +240,7 @@ fn render_autoconf(
             continue;
         }
         const name = it.rest();
-        const kv = values_copy.fetchRemove(name) orelse {
+        const kv = values_copy.fetchSwapRemove(name) orelse {
             std.debug.print("{s}:{d}: error: unspecified config header value: '{s}'\n", .{
                 src_path, line_index + 1, name,
             });
@@ -202,12 +250,8 @@ fn render_autoconf(
         try renderValue(output, name, kv.value);
     }
 
-    {
+    for (values_copy.keys()) |name| {
-        var it = values_copy.iterator();
+        std.debug.print("{s}: error: config header value unused: '{s}'\n", .{ src_path, name });
-        while (it.next()) |entry| {
-            const name = entry.key_ptr.*;
-            std.debug.print("{s}: error: config header value unused: '{s}'\n", .{ src_path, name });
-        }
     }
 
     if (any_errors) {
@@ -218,9 +262,12 @@ fn render_autoconf(
 fn render_cmake(
     contents: []const u8,
     output: *std.ArrayList(u8),
-    values_copy: *std.StringHashMap(Value),
+    values: std.StringArrayHashMap(Value),
     src_path: []const u8,
 ) !void {
+    var values_copy = try values.clone();
+    defer values_copy.deinit();
+
     var any_errors = false;
     var line_index: u32 = 0;
     var line_it = std.mem.split(u8, contents, "\n");
@@ -244,7 +291,7 @@ fn render_cmake(
             any_errors = true;
             continue;
         };
-        const kv = values_copy.fetchRemove(name) orelse {
+        const kv = values_copy.fetchSwapRemove(name) orelse {
             std.debug.print("{s}:{d}: error: unspecified config header value: '{s}'\n", .{
                 src_path, line_index + 1, name,
             });
@@ -254,12 +301,8 @@ fn render_cmake(
         try renderValue(output, name, kv.value);
     }
 
-    {
+    for (values_copy.keys()) |name| {
-        var it = values_copy.iterator();
+        std.debug.print("{s}: error: config header value unused: '{s}'\n", .{ src_path, name });
-        while (it.next()) |entry| {
-            const name = entry.key_ptr.*;
-            std.debug.print("{s}: error: config header value unused: '{s}'\n", .{ src_path, name });
-        }
     }
 
     if (any_errors) {
@@ -267,6 +310,36 @@ fn render_cmake(
     }
 }
 
+fn render_blank(
+    output: *std.ArrayList(u8),
+    defines: std.StringArrayHashMap(Value),
+    include_path: []const u8,
+) !void {
+    const include_guard_name = try output.allocator.dupe(u8, include_path);
+    for (include_guard_name) |*byte| {
+        switch (byte.*) {
+            'a'...'z' => byte.* = byte.* - 'a' + 'A',
+            'A'...'Z', '0'...'9' => continue,
+            else => byte.* = '_',
+        }
+    }
+
+    try output.appendSlice("#ifndef ");
+    try output.appendSlice(include_guard_name);
+    try output.appendSlice("\n#define ");
+    try output.appendSlice(include_guard_name);
+    try output.appendSlice("\n");
+
+    const values = defines.values();
+    for (defines.keys()) |name, i| {
+        try renderValue(output, name, values[i]);
+    }
+
+    try output.appendSlice("#endif /* ");
+    try output.appendSlice(include_guard_name);
+    try output.appendSlice(" */\n");
+}
+
 fn renderValue(output: *std.ArrayList(u8), name: []const u8, value: Value) !void {
     switch (value) {
         .undef => {

lib/std/Build/TranslateCStep.zig

@@ -15,7 +15,6 @@ builder: *std.Build,
 source: std.Build.FileSource,
 include_dirs: std.ArrayList([]const u8),
 c_macros: std.ArrayList([]const u8),
-output_dir: ?[]const u8,
 out_basename: []const u8,
 target: CrossTarget,
 optimize: std.builtin.OptimizeMode,
@@ -36,7 +35,6 @@ pub fn create(builder: *std.Build, options: Options) *TranslateCStep {
         .source = source,
         .include_dirs = std.ArrayList([]const u8).init(builder.allocator),
         .c_macros = std.ArrayList([]const u8).init(builder.allocator),
-        .output_dir = null,
         .out_basename = undefined,
         .target = options.target,
         .optimize = options.optimize,
@@ -122,15 +120,10 @@ fn make(step: *Step) !void {
     const output_path = mem.trimRight(u8, output_path_nl, "\r\n");
 
     self.out_basename = fs.path.basename(output_path);
-    if (self.output_dir) |output_dir| {
+    const output_dir = fs.path.dirname(output_path).?;
-        const full_dest = try fs.path.join(self.builder.allocator, &[_][]const u8{ output_dir, self.out_basename });
-        try self.builder.updateFile(output_path, full_dest);
-    } else {
-        self.output_dir = fs.path.dirname(output_path).?;
-    }
 
     self.output_file.path = try fs.path.join(
         self.builder.allocator,
-        &[_][]const u8{ self.output_dir.?, self.out_basename },
+        &[_][]const u8{ output_dir, self.out_basename },
     );
 }

lib/std/Build/WriteFileStep.zig

@@ -9,7 +9,6 @@ pub const base_id = .write_file;
 
 step: Step,
 builder: *std.Build,
-output_dir: []const u8,
 files: std.TailQueue(File),
 
 pub const File = struct {
@@ -23,7 +22,6 @@ pub fn init(builder: *std.Build) WriteFileStep {
         .builder = builder,
         .step = Step.init(.write_file, "writefile", builder.allocator, make),
         .files = .{},
-        .output_dir = undefined,
     };
 }
 
@@ -87,11 +85,11 @@ fn make(step: *Step) !void {
         .{std.fmt.fmtSliceHexLower(&digest)},
     ) catch unreachable;
 
-    self.output_dir = try fs.path.join(self.builder.allocator, &[_][]const u8{
+    const output_dir = try fs.path.join(self.builder.allocator, &[_][]const u8{
         self.builder.cache_root, "o", &hash_basename,
     });
-    var dir = fs.cwd().makeOpenPath(self.output_dir, .{}) catch |err| {
+    var dir = fs.cwd().makeOpenPath(output_dir, .{}) catch |err| {
-        std.debug.print("unable to make path {s}: {s}\n", .{ self.output_dir, @errorName(err) });
+        std.debug.print("unable to make path {s}: {s}\n", .{ output_dir, @errorName(err) });
         return err;
     };
     defer dir.close();
@@ -101,14 +99,14 @@ fn make(step: *Step) !void {
             dir.writeFile(node.data.basename, node.data.bytes) catch |err| {
                 std.debug.print("unable to write {s} into {s}: {s}\n", .{
                     node.data.basename,
-                    self.output_dir,
+                    output_dir,
                     @errorName(err),
                 });
                 return err;
             };
             node.data.source.path = try fs.path.join(
                 self.builder.allocator,
-                &[_][]const u8{ self.output_dir, node.data.basename },
+                &[_][]const u8{ output_dir, node.data.basename },
             );
         }
     }