Dan Willemsen | 38f2dba | 2016-07-08 14:54:35 -0700 | [diff] [blame^] | 1 | // Copyright 2013 The Go Authors. All rights reserved. |
Dan Willemsen | 09eb3b1 | 2015-09-16 14:34:17 -0700 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package main |
| 6 | |
| 7 | import ( |
| 8 | "bytes" |
| 9 | "fmt" |
| 10 | "os" |
| 11 | "strings" |
| 12 | "unicode" |
| 13 | ) |
| 14 | |
| 15 | var ( |
| 16 | nl = []byte("\n") |
| 17 | slashSlash = []byte("//") |
| 18 | plusBuild = []byte("+build") |
| 19 | ) |
| 20 | |
| 21 | // checkBuildTag checks that build tags are in the correct location and well-formed. |
| 22 | func checkBuildTag(name string, data []byte) { |
| 23 | if !vet("buildtags") { |
| 24 | return |
| 25 | } |
| 26 | lines := bytes.SplitAfter(data, nl) |
| 27 | |
| 28 | // Determine cutpoint where +build comments are no longer valid. |
| 29 | // They are valid in leading // comments in the file followed by |
| 30 | // a blank line. |
| 31 | var cutoff int |
| 32 | for i, line := range lines { |
| 33 | line = bytes.TrimSpace(line) |
| 34 | if len(line) == 0 { |
| 35 | cutoff = i |
| 36 | continue |
| 37 | } |
| 38 | if bytes.HasPrefix(line, slashSlash) { |
| 39 | continue |
| 40 | } |
| 41 | break |
| 42 | } |
| 43 | |
| 44 | for i, line := range lines { |
| 45 | line = bytes.TrimSpace(line) |
| 46 | if !bytes.HasPrefix(line, slashSlash) { |
| 47 | continue |
| 48 | } |
| 49 | text := bytes.TrimSpace(line[2:]) |
| 50 | if bytes.HasPrefix(text, plusBuild) { |
| 51 | fields := bytes.Fields(text) |
| 52 | if !bytes.Equal(fields[0], plusBuild) { |
| 53 | // Comment is something like +buildasdf not +build. |
| 54 | fmt.Fprintf(os.Stderr, "%s:%d: possible malformed +build comment\n", name, i+1) |
| 55 | continue |
| 56 | } |
| 57 | if i >= cutoff { |
| 58 | fmt.Fprintf(os.Stderr, "%s:%d: +build comment must appear before package clause and be followed by a blank line\n", name, i+1) |
| 59 | setExit(1) |
| 60 | continue |
| 61 | } |
| 62 | // Check arguments. |
| 63 | Args: |
| 64 | for _, arg := range fields[1:] { |
| 65 | for _, elem := range strings.Split(string(arg), ",") { |
| 66 | if strings.HasPrefix(elem, "!!") { |
| 67 | fmt.Fprintf(os.Stderr, "%s:%d: invalid double negative in build constraint: %s\n", name, i+1, arg) |
| 68 | setExit(1) |
| 69 | break Args |
| 70 | } |
| 71 | if strings.HasPrefix(elem, "!") { |
| 72 | elem = elem[1:] |
| 73 | } |
| 74 | for _, c := range elem { |
| 75 | if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' && c != '.' { |
| 76 | fmt.Fprintf(os.Stderr, "%s:%d: invalid non-alphanumeric build constraint: %s\n", name, i+1, arg) |
| 77 | setExit(1) |
| 78 | break Args |
| 79 | } |
| 80 | } |
| 81 | } |
| 82 | } |
| 83 | continue |
| 84 | } |
| 85 | // Comment with +build but not at beginning. |
| 86 | if bytes.Contains(line, plusBuild) && i < cutoff { |
| 87 | fmt.Fprintf(os.Stderr, "%s:%d: possible malformed +build comment\n", name, i+1) |
| 88 | continue |
| 89 | } |
| 90 | } |
| 91 | } |