github.com/solo-io/cue@v0.4.7/internal/filetypes/util.go (about)

     1  // Copyright 2020 CUE 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 filetypes
    16  
    17  import (
    18  	"path/filepath"
    19  	"strings"
    20  
    21  	"github.com/solo-io/cue/cue/ast"
    22  )
    23  
    24  // IsPackage reports whether a command-line argument is a package based on its
    25  // lexical representation alone.
    26  func IsPackage(s string) bool {
    27  	if s == "." || s == ".." {
    28  		return true
    29  	}
    30  	if s == "-" {
    31  		return false
    32  	}
    33  
    34  	// This goes of the assumption that file names may not have a `:` in their
    35  	// name in cue.
    36  	// A filename must have an extension or be preceded by a qualifier argument.
    37  	// So strings of the form foo/bar:baz, where bar is a valid identifier and
    38  	// absolute package
    39  	if p := strings.LastIndexByte(s, ':'); p > 0 {
    40  		if !ast.IsValidIdent(s[p+1:]) {
    41  			return false
    42  		}
    43  		// For a non-pkg, the part before : may only be lowercase and '+'.
    44  		// In addition, a package necessarily must have a slash of some form.
    45  		return strings.ContainsAny(s[:p], `/.\`)
    46  	}
    47  
    48  	// Assuming we terminate search for packages once a scoped qualifier is
    49  	// found, we know that any file without an extension (except maybe '-')
    50  	// is invalid. We can therefore assume it is a package.
    51  	// The section may still contain a dot, for instance ./foo/. or ./foo/...
    52  	return strings.TrimLeft(filepath.Ext(s), ".") == ""
    53  
    54  	// NOTE/TODO: we have not needed to check whether it is an absolute package
    55  	// or whether the package starts with a dot. Potentially we could thus relax
    56  	// the requirement that packages be dots if it is clear that the package
    57  	// name will not interfere with command names in all circumstances.
    58  }