v/vlib/toml/checker/checker.v

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// Copyright (c) 2021 Lars Pontoppidan. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module checker
import toml.ast
import toml.ast.walker
// import toml.util
import toml.token
import toml.scanner
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pub const allowed_basic_escape_chars = [`u`, `U`, `b`, `t`, `n`, `f`, `r`, `"`, `\\`]
// Checker checks a tree of TOML `ast.Value`'s for common errors.
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pub struct Checker {
scanner &scanner.Scanner
}
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// check checks the `ast.Value` and all it's children
// for common errors.
pub fn (c Checker) check(n &ast.Value) ? {
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walker.walk(c, n) ?
}
fn (c Checker) visit(value &ast.Value) ? {
match value {
ast.Bool {
c.check_boolean(value) ?
}
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ast.Number {
c.check_number(value) ?
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}
ast.Quoted {
c.check_quoted(value) ?
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}
else {
// TODO add more checks to make BurntSushi/toml-test invalid TOML pass
}
}
}
// excerpt returns a string of the characters surrounding`
fn (c Checker) excerpt(tp token.Position) string {
return c.scanner.excerpt(tp.pos, 10)
}
fn is_hex_bin_oct(hbo string) bool {
return hbo.len > 2 && (hbo.starts_with('0x') || hbo.starts_with('0o') || hbo.starts_with('0b'))
}
fn has_repeating(str string, repeats []rune) bool {
for i, r in str {
if r in repeats && i + 1 < str.len {
if r == str[i + 1] {
return true
}
}
}
return false
}
fn (c Checker) check_number(num ast.Number) ? {
lit := num.text
if lit in ['0', '0.0', '+0', '-0', '+0.0', '-0.0', '0e0', '+0e0', '-0e0', '0e00'] {
return
}
if lit.contains('_') {
if lit.starts_with('_') || lit.ends_with('_') {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not start or end with `_` in ...${c.excerpt(num.pos)}...')
}
if lit.contains('__') {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not have more than one underscore (`_`) in ...${c.excerpt(num.pos)}...')
}
}
mut hex_bin_oct := is_hex_bin_oct(lit)
is_hex := lit.contains('0x')
is_float := lit.to_lower().all_before('e').contains('.')
has_exponent_notation := lit.to_lower().contains('e')
float_decimal_index := lit.index('.') or { -1 }
// mut is_first_digit := byte(lit[0]).is_digit()
mut ascii := byte(lit[0]).ascii_str()
is_sign_prefixed := lit[0] in [`+`, `-`]
if is_sign_prefixed { // +/- ...
n := lit[1..]
hex_bin_oct = is_hex_bin_oct(n)
if hex_bin_oct {
ascii = byte(lit[0]).ascii_str()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (hex, octal and binary) can not start with `$ascii` in ...${c.excerpt(num.pos)}...')
}
// is_first_digit = byte(n[0]).is_digit()
if lit.len > 1 && n.starts_with('0') {
ascii = byte(n[0]).ascii_str()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not start with `$ascii` in ...${c.excerpt(num.pos)}...')
}
} else {
if !hex_bin_oct {
if !is_float && lit[0] == `0` {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not start with a zero in ...${c.excerpt(num.pos)}...')
}
if is_float && lit[0] == `0` && float_decimal_index > 1 {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not start with a zero in ...${c.excerpt(num.pos)}...')
}
}
}
if has_repeating(lit, [`_`, `.`, `x`, `o`, `b`]) {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not have $scanner.digit_extras as repeating characters in ...${c.excerpt(num.pos)}...')
}
if hex_bin_oct {
third := lit[2]
if third in scanner.digit_extras {
ascii = byte(third).ascii_str()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (hex, octal and binary) can not have `$ascii` in ...${c.excerpt(num.pos)}...')
}
}
if has_exponent_notation {
if lit.to_lower().all_after('e').contains('.') {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (with exponent) can not have a decimal point in ...${c.excerpt(num.pos)}...')
}
if !is_hex && lit.to_lower().count('e') > 1 {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (with exponent) can only have one exponent in ...${c.excerpt(num.pos)}...')
}
}
if is_float {
if lit.count('.') > 1 {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (float) can only have one decimal point in ...${c.excerpt(num.pos)}...')
}
last := lit[lit.len - 1]
if last in scanner.digit_extras {
ascii = byte(last).ascii_str()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (float) can not start with `$ascii` in ...${c.excerpt(num.pos)}...')
}
if lit.contains('_.') || lit.contains('._') {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (float) can not have underscores before or after the decimal point in ...${c.excerpt(num.pos)}...')
}
if lit.contains('e.') || lit.contains('.e') || lit.contains('E.') || lit.contains('.E') {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" (float) can not have underscores before or after the decimal point in ...${c.excerpt(num.pos)}...')
}
} else {
if lit.len > 1 && lit.starts_with('0') && lit[1] !in [`x`, `o`, `b`] {
ascii = byte(lit[0]).ascii_str()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' numbers like "$lit" can not start with `$ascii` in ...${c.excerpt(num.pos)}...')
}
}
}
fn (c Checker) check_boolean(b ast.Bool) ? {
lit := b.text
if lit in ['true', 'false'] {
return
}
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' boolean values like "$lit" can only be `true` or `false` literals, not `$lit` in ...${c.excerpt(b.pos)}...')
}
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fn (c Checker) check_quoted(q ast.Quoted) ? {
lit := q.text
quote := q.quote.ascii_str()
triple_quote := quote + quote + quote
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if q.is_multiline && lit.ends_with(triple_quote) {
return error(@MOD + '.' + @STRUCT + '.' + @FN +
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' string values like "$lit" is has unbalanced quote literals `q.quote` in ...${c.excerpt(q.pos)}...')
}
c.check_quoted_escapes(q) ?
}
// check_quoted_escapes returns an error for any disallowed escape sequences.
// Delimiters in TOML has significant meaning:
// '/''' delimits *literal* strings (WYSIWYG / What-you-see-is-what-you-get)
// "/""" delimits *basic* strings
// Allowed escapes in *basic* strings are:
// \b - backspace (U+0008)
// \t - tab (U+0009)
// \n - linefeed (U+000A)
// \f - form feed (U+000C)
// \r - carriage return (U+000D)
// \" - quote (U+0022)
// \\ - backslash (U+005C)
// \uXXXX - unicode (U+XXXX)
// \UXXXXXXXX - unicode (U+XXXXXXXX)
fn (c Checker) check_quoted_escapes(q ast.Quoted) ? {
// Setup a scanner in stack memory for easier navigation.
mut s := scanner.new_simple(q.text) ?
is_basic := q.quote == `\"`
for {
ch := s.next()
if ch == -1 {
break
}
ch_byte := byte(ch)
if ch == `\\` {
next_ch := byte(s.at())
if next_ch == `\\` {
s.next()
continue
}
escape := ch_byte.ascii_str() + next_ch.ascii_str()
if is_basic {
if q.is_multiline {
if next_ch == byte(32) && s.peek(1) == byte(92) {
st := s.state()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' can not escape whitespaces before escapes in multi-line strings (`\\ \\`) at `$escape` ($st.line_nr,$st.col) in ...${c.excerpt(q.pos)}...')
}
if next_ch in [`\t`, `\n`, ` `] {
s.next()
continue
}
}
if next_ch !in checker.allowed_basic_escape_chars {
st := s.state()
return error(@MOD + '.' + @STRUCT + '.' + @FN +
' unknown basic string escape character `$next_ch.ascii_str()` in `$escape` ($st.line_nr,$st.col) in ...${c.excerpt(q.pos)}...')
}
}
}
}
}