go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/lucicfg/genctx.go (about)

     1  // Copyright 2018 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package lucicfg
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"go.starlark.net/starlark"
    21  	"go.starlark.net/starlarkstruct"
    22  )
    23  
    24  // genCtx is a starlark struct that represents the state passed to generator
    25  // callbacks (as first and only argument).
    26  type genCtx struct {
    27  	starlarkstruct.Struct
    28  
    29  	output *outputBuilder
    30  	roots  map[string]string // name of the set => its root directory
    31  }
    32  
    33  func newGenCtx() *genCtx {
    34  	ctx := &genCtx{
    35  		output: newOutputBuilder(),
    36  		roots:  map[string]string{},
    37  	}
    38  	ctx.Struct = *starlarkstruct.FromStringDict(starlark.String("gen_ctx"), starlark.StringDict{
    39  		"output":             ctx.output,
    40  		"declare_config_set": starlark.NewBuiltin("declare_config_set", ctx.declareConfigSetImpl),
    41  	})
    42  	return ctx
    43  }
    44  
    45  func (c *genCtx) declareConfigSetImpl(_ *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
    46  	var name starlark.String
    47  	var root starlark.String
    48  	err := starlark.UnpackArgs("declare_config_set", args, kwargs,
    49  		"name", &name,
    50  		"root", &root)
    51  	if err != nil {
    52  		return nil, err
    53  	}
    54  	nameS := name.GoString()
    55  
    56  	// Paths must be within the config output directory, "../" is not allowed.
    57  	rootS, err := cleanRelativePath("", root.GoString(), false)
    58  	if err != nil {
    59  		return nil, fmt.Errorf("declare_config_set: root - %s", err)
    60  	}
    61  
    62  	// It is OK to redeclare exact same root. It is not OK to change it.
    63  	if existing, ok := c.roots[nameS]; ok && existing != rootS {
    64  		return nil, fmt.Errorf("declare_config_set: set %q has already been declared", nameS)
    65  	}
    66  	c.roots[nameS] = rootS
    67  
    68  	return starlark.None, nil
    69  }
    70  
    71  func (c *genCtx) assembleOutput(includePBHeader bool) (Output, error) {
    72  	files, err := c.output.finalize(includePBHeader)
    73  	return Output{
    74  		Data:  files,
    75  		Roots: c.roots,
    76  	}, err
    77  }
    78  
    79  func init() {
    80  	// new_gen_ctx() makes a new empty generator context object.
    81  	declNative("new_gen_ctx", func(call nativeCall) (starlark.Value, error) {
    82  		if err := call.unpack(0); err != nil {
    83  			return nil, err
    84  		}
    85  		return newGenCtx(), nil
    86  	})
    87  }