github.com/anakojm/hugo-katex@v0.0.0-20231023141351-42d6f5de9c0b/parser/metadecoders/format.go (about)

     1  // Copyright 2018 The Hugo Authors. All rights reserved.
     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  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package metadecoders
    15  
    16  import (
    17  	"path/filepath"
    18  	"strings"
    19  )
    20  
    21  type Format string
    22  
    23  const (
    24  	// These are the supported metadata  formats in Hugo. Most of these are also
    25  	// supported as /data formats.
    26  	ORG  Format = "org"
    27  	JSON Format = "json"
    28  	TOML Format = "toml"
    29  	YAML Format = "yaml"
    30  	CSV  Format = "csv"
    31  	XML  Format = "xml"
    32  )
    33  
    34  // FormatFromStrings returns the first non-empty Format from the given strings.
    35  func FormatFromStrings(ss ...string) Format {
    36  	for _, s := range ss {
    37  		if f := FormatFromString(s); f != "" {
    38  			return f
    39  		}
    40  	}
    41  	return ""
    42  }
    43  
    44  // FormatFromString turns formatStr, typically a file extension without any ".",
    45  // into a Format. It returns an empty string for unknown formats.
    46  func FormatFromString(formatStr string) Format {
    47  	formatStr = strings.ToLower(formatStr)
    48  	if strings.Contains(formatStr, ".") {
    49  		// Assume a filename
    50  		formatStr = strings.TrimPrefix(filepath.Ext(formatStr), ".")
    51  	}
    52  	switch formatStr {
    53  	case "yaml", "yml":
    54  		return YAML
    55  	case "json":
    56  		return JSON
    57  	case "toml":
    58  		return TOML
    59  	case "org":
    60  		return ORG
    61  	case "csv":
    62  		return CSV
    63  	case "xml":
    64  		return XML
    65  	}
    66  
    67  	return ""
    68  }
    69  
    70  // FormatFromContentString tries to detect the format (JSON, YAML, TOML or XML)
    71  // in the given string.
    72  // It return an empty string if no format could be detected.
    73  func (d Decoder) FormatFromContentString(data string) Format {
    74  	csvIdx := strings.IndexRune(data, d.Delimiter)
    75  	jsonIdx := strings.Index(data, "{")
    76  	yamlIdx := strings.Index(data, ":")
    77  	xmlIdx := strings.Index(data, "<")
    78  	tomlIdx := strings.Index(data, "=")
    79  
    80  	if isLowerIndexThan(csvIdx, jsonIdx, yamlIdx, xmlIdx, tomlIdx) {
    81  		return CSV
    82  	}
    83  
    84  	if isLowerIndexThan(jsonIdx, yamlIdx, xmlIdx, tomlIdx) {
    85  		return JSON
    86  	}
    87  
    88  	if isLowerIndexThan(yamlIdx, xmlIdx, tomlIdx) {
    89  		return YAML
    90  	}
    91  
    92  	if isLowerIndexThan(xmlIdx, tomlIdx) {
    93  		return XML
    94  	}
    95  
    96  	if tomlIdx != -1 {
    97  		return TOML
    98  	}
    99  
   100  	return ""
   101  }
   102  
   103  func isLowerIndexThan(first int, others ...int) bool {
   104  	if first == -1 {
   105  		return false
   106  	}
   107  	for _, other := range others {
   108  		if other != -1 && other < first {
   109  			return false
   110  		}
   111  	}
   112  
   113  	return true
   114  }