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1 package toml |
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2 |
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3 import ( |
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4 "fmt" |
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5 "strconv" |
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6 "strings" |
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7 |
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8 "github.com/pelletier/go-toml/v2/internal/danger" |
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9 ) |
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10 |
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11 // DecodeError represents an error encountered during the parsing or decoding |
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12 // of a TOML document. |
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13 // |
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14 // In addition to the error message, it contains the position in the document |
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15 // where it happened, as well as a human-readable representation that shows |
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16 // where the error occurred in the document. |
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17 type DecodeError struct { |
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18 message string |
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19 line int |
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20 column int |
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21 key Key |
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22 |
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23 human string |
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24 } |
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25 |
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26 // StrictMissingError occurs in a TOML document that does not have a |
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27 // corresponding field in the target value. It contains all the missing fields |
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28 // in Errors. |
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29 // |
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30 // Emitted by Decoder when DisallowUnknownFields() was called. |
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31 type StrictMissingError struct { |
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32 // One error per field that could not be found. |
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33 Errors []DecodeError |
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34 } |
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35 |
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36 // Error returns the canonical string for this error. |
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37 func (s *StrictMissingError) Error() string { |
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38 return "strict mode: fields in the document are missing in the target struct" |
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39 } |
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40 |
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41 // String returns a human readable description of all errors. |
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42 func (s *StrictMissingError) String() string { |
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43 var buf strings.Builder |
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44 |
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45 for i, e := range s.Errors { |
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46 if i > 0 { |
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47 buf.WriteString("\n---\n") |
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48 } |
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49 |
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50 buf.WriteString(e.String()) |
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51 } |
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52 |
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53 return buf.String() |
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54 } |
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55 |
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56 type Key []string |
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57 |
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58 // internal version of DecodeError that is used as the base to create a |
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59 // DecodeError with full context. |
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60 type decodeError struct { |
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61 highlight []byte |
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62 message string |
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63 key Key // optional |
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64 } |
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65 |
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66 func (de *decodeError) Error() string { |
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67 return de.message |
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68 } |
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69 |
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70 func newDecodeError(highlight []byte, format string, args ...interface{}) error { |
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71 return &decodeError{ |
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72 highlight: highlight, |
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73 message: fmt.Errorf(format, args...).Error(), |
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74 } |
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75 } |
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76 |
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77 // Error returns the error message contained in the DecodeError. |
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78 func (e *DecodeError) Error() string { |
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79 return "toml: " + e.message |
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80 } |
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81 |
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82 // String returns the human-readable contextualized error. This string is multi-line. |
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83 func (e *DecodeError) String() string { |
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84 return e.human |
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85 } |
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86 |
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87 // Position returns the (line, column) pair indicating where the error |
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88 // occurred in the document. Positions are 1-indexed. |
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89 func (e *DecodeError) Position() (row int, column int) { |
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90 return e.line, e.column |
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91 } |
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92 |
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93 // Key that was being processed when the error occurred. The key is present only |
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94 // if this DecodeError is part of a StrictMissingError. |
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95 func (e *DecodeError) Key() Key { |
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96 return e.key |
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97 } |
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98 |
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99 // decodeErrorFromHighlight creates a DecodeError referencing a highlighted |
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100 // range of bytes from document. |
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101 // |
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102 // highlight needs to be a sub-slice of document, or this function panics. |
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103 // |
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104 // The function copies all bytes used in DecodeError, so that document and |
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105 // highlight can be freely deallocated. |
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106 // |
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107 //nolint:funlen |
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108 func wrapDecodeError(document []byte, de *decodeError) *DecodeError { |
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109 offset := danger.SubsliceOffset(document, de.highlight) |
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110 |
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111 errMessage := de.Error() |
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112 errLine, errColumn := positionAtEnd(document[:offset]) |
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113 before, after := linesOfContext(document, de.highlight, offset, 3) |
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114 |
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115 var buf strings.Builder |
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116 |
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117 maxLine := errLine + len(after) - 1 |
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118 lineColumnWidth := len(strconv.Itoa(maxLine)) |
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119 |
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120 // Write the lines of context strictly before the error. |
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121 for i := len(before) - 1; i > 0; i-- { |
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122 line := errLine - i |
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123 buf.WriteString(formatLineNumber(line, lineColumnWidth)) |
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124 buf.WriteString("|") |
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125 |
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126 if len(before[i]) > 0 { |
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127 buf.WriteString(" ") |
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128 buf.Write(before[i]) |
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129 } |
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130 |
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131 buf.WriteRune('\n') |
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132 } |
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133 |
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134 // Write the document line that contains the error. |
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135 |
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136 buf.WriteString(formatLineNumber(errLine, lineColumnWidth)) |
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137 buf.WriteString("| ") |
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138 |
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139 if len(before) > 0 { |
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140 buf.Write(before[0]) |
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141 } |
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142 |
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143 buf.Write(de.highlight) |
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144 |
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145 if len(after) > 0 { |
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146 buf.Write(after[0]) |
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147 } |
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148 |
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149 buf.WriteRune('\n') |
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150 |
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151 // Write the line with the error message itself (so it does not have a line |
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152 // number). |
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153 |
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154 buf.WriteString(strings.Repeat(" ", lineColumnWidth)) |
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155 buf.WriteString("| ") |
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156 |
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157 if len(before) > 0 { |
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158 buf.WriteString(strings.Repeat(" ", len(before[0]))) |
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159 } |
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160 |
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161 buf.WriteString(strings.Repeat("~", len(de.highlight))) |
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162 |
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163 if len(errMessage) > 0 { |
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164 buf.WriteString(" ") |
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165 buf.WriteString(errMessage) |
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166 } |
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167 |
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168 // Write the lines of context strictly after the error. |
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169 |
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170 for i := 1; i < len(after); i++ { |
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171 buf.WriteRune('\n') |
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172 line := errLine + i |
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173 buf.WriteString(formatLineNumber(line, lineColumnWidth)) |
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174 buf.WriteString("|") |
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175 |
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176 if len(after[i]) > 0 { |
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177 buf.WriteString(" ") |
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178 buf.Write(after[i]) |
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179 } |
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180 } |
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181 |
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182 return &DecodeError{ |
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183 message: errMessage, |
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184 line: errLine, |
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185 column: errColumn, |
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186 key: de.key, |
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187 human: buf.String(), |
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188 } |
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189 } |
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190 |
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191 func formatLineNumber(line int, width int) string { |
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192 format := "%" + strconv.Itoa(width) + "d" |
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193 |
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194 return fmt.Sprintf(format, line) |
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195 } |
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196 |
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197 func linesOfContext(document []byte, highlight []byte, offset int, linesAround int) ([][]byte, [][]byte) { |
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198 return beforeLines(document, offset, linesAround), afterLines(document, highlight, offset, linesAround) |
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199 } |
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200 |
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201 func beforeLines(document []byte, offset int, linesAround int) [][]byte { |
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202 var beforeLines [][]byte |
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203 |
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204 // Walk the document backward from the highlight to find previous lines |
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205 // of context. |
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206 rest := document[:offset] |
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207 backward: |
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208 for o := len(rest) - 1; o >= 0 && len(beforeLines) <= linesAround && len(rest) > 0; { |
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209 switch { |
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210 case rest[o] == '\n': |
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211 // handle individual lines |
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212 beforeLines = append(beforeLines, rest[o+1:]) |
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213 rest = rest[:o] |
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214 o = len(rest) - 1 |
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215 case o == 0: |
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216 // add the first line only if it's non-empty |
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217 beforeLines = append(beforeLines, rest) |
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218 |
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219 break backward |
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220 default: |
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221 o-- |
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222 } |
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223 } |
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224 |
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225 return beforeLines |
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226 } |
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227 |
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228 func afterLines(document []byte, highlight []byte, offset int, linesAround int) [][]byte { |
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229 var afterLines [][]byte |
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230 |
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231 // Walk the document forward from the highlight to find the following |
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232 // lines of context. |
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233 rest := document[offset+len(highlight):] |
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234 forward: |
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235 for o := 0; o < len(rest) && len(afterLines) <= linesAround; { |
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236 switch { |
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237 case rest[o] == '\n': |
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238 // handle individual lines |
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239 afterLines = append(afterLines, rest[:o]) |
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240 rest = rest[o+1:] |
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241 o = 0 |
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242 |
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243 case o == len(rest)-1: |
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244 // add last line only if it's non-empty |
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245 afterLines = append(afterLines, rest) |
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246 |
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247 break forward |
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248 default: |
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249 o++ |
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250 } |
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251 } |
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252 |
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253 return afterLines |
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254 } |
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255 |
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256 func positionAtEnd(b []byte) (row int, column int) { |
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257 row = 1 |
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258 column = 1 |
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259 |
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260 for _, c := range b { |
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261 if c == '\n' { |
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262 row++ |
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263 column = 1 |
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264 } else { |
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265 column++ |
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266 } |
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267 } |
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268 |
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269 return |
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270 } |