github.com/keysonzzz/kmg@v0.0.0-20151121023212-05317bfd7d39/encoding/kmgYaml/yaml_emitter_analyze.go

package kmgYaml

import (
	"bytes"
)

// Check if a %YAML directive is valid.
func yaml_emitter_analyze_version_directive(emitter *yaml_emitter_t, version_directive *yaml_version_directive_t) bool {
	if version_directive.major != 1 || version_directive.minor != 1 {
		return yaml_emitter_set_emitter_error(emitter, "incompatible %YAML directive")
	}
	return true
}

// Check if a %TAG directive is valid.
func yaml_emitter_analyze_tag_directive(emitter *yaml_emitter_t, tag_directive *yaml_tag_directive_t) bool {
	handle := tag_directive.handle
	prefix := tag_directive.prefix
	if len(handle) == 0 {
		return yaml_emitter_set_emitter_error(emitter, "tag handle must not be empty")
	}
	if handle[0] != '!' {
		return yaml_emitter_set_emitter_error(emitter, "tag handle must start with '!'")
	}
	if handle[len(handle)-1] != '!' {
		return yaml_emitter_set_emitter_error(emitter, "tag handle must end with '!'")
	}
	for i := 1; i < len(handle)-1; i += width(handle[i]) {
		if !is_alpha(handle, i) {
			return yaml_emitter_set_emitter_error(emitter, "tag handle must contain alphanumerical characters only")
		}
	}
	if len(prefix) == 0 {
		return yaml_emitter_set_emitter_error(emitter, "tag prefix must not be empty")
	}
	return true
}

// Check if an anchor is valid.
func yaml_emitter_analyze_anchor(emitter *yaml_emitter_t, anchor []byte, alias bool) bool {
	if len(anchor) == 0 {
		problem := "anchor value must not be empty"
		if alias {
			problem = "alias value must not be empty"
		}
		return yaml_emitter_set_emitter_error(emitter, problem)
	}
	for i := 0; i < len(anchor); i += width(anchor[i]) {
		if !is_alpha(anchor, i) {
			problem := "anchor value must contain alphanumerical characters only"
			if alias {
				problem = "alias value must contain alphanumerical characters only"
			}
			return yaml_emitter_set_emitter_error(emitter, problem)
		}
	}
	emitter.anchor_data.anchor = anchor
	emitter.anchor_data.alias = alias
	return true
}

// Check if a tag is valid.
func yaml_emitter_analyze_tag(emitter *yaml_emitter_t, tag []byte) bool {
	if len(tag) == 0 {
		return yaml_emitter_set_emitter_error(emitter, "tag value must not be empty")
	}
	for i := 0; i < len(emitter.tag_directives); i++ {
		tag_directive := &emitter.tag_directives[i]
		if bytes.HasPrefix(tag, tag_directive.prefix) {
			emitter.tag_data.handle = tag_directive.handle
			emitter.tag_data.suffix = tag[len(tag_directive.prefix):]
		}
		return true
	}
	emitter.tag_data.suffix = tag
	return true
}

// Check if a scalar is valid.
func yaml_emitter_analyze_scalar(emitter *yaml_emitter_t, value []byte) bool {
	var (
		block_indicators   = false
		flow_indicators    = false
		line_breaks        = false
		special_characters = false

		leading_space  = false
		leading_break  = false
		trailing_space = false
		trailing_break = false
		break_space    = false
		space_break    = false

		preceeded_by_whitespace = false
		followed_by_whitespace  = false
		previous_space          = false
		previous_break          = false
	)

	emitter.scalar_data.value = value

	if len(value) == 0 {
		emitter.scalar_data.multiline = false
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = true
		emitter.scalar_data.single_quoted_allowed = true
		emitter.scalar_data.block_allowed = false
		return true
	}

	if (value[0] == '-' && value[1] == '-' && value[2] == '-') || (value[0] == '.' && value[1] == '.' && value[2] == '.') {
		block_indicators = true
		flow_indicators = true
	}

	preceeded_by_whitespace = true
	for i, w := 0, 0; i < len(value); i += w {
		w = width(value[i]) //bug origin width(value[0])
		followed_by_whitespace = i+w >= len(value) || is_blank(value, i+w)

		if i == 0 {
			switch value[i] {
			case '#', ',', '[', ']', '{', '}', '&', '*', '!', '|', '>', '\'', '"', '%', '@', '`':
				flow_indicators = true
				block_indicators = true
			case '?', ':':
				flow_indicators = true
				if followed_by_whitespace {
					block_indicators = true
				}
			case '-':
				if followed_by_whitespace {
					flow_indicators = true
					block_indicators = true
				}
			}
		} else {
			switch value[i] {
			case ',', '?', '[', ']', '{', '}':
				flow_indicators = true
			case ':':
				flow_indicators = true
				if followed_by_whitespace {
					block_indicators = true
				}
			case '#':
				if preceeded_by_whitespace {
					flow_indicators = true
					block_indicators = true
				}
			}
		}

		if !is_printable(value, i) || !is_ascii(value, i) && !emitter.unicode {
			special_characters = true
		}
		if is_space(value, i) {
			if i == 0 {
				leading_space = true
			}
			if i+width(value[i]) == len(value) {
				trailing_space = true
			}
			if previous_break {
				break_space = true
			}
			previous_space = true
			previous_break = false
		} else if is_break(value, i) {
			line_breaks = true
			if i == 0 {
				leading_break = true
			}
			if i+width(value[i]) == len(value) {
				trailing_break = true
			}
			if previous_space {
				space_break = true
			}
			previous_space = false
			previous_break = true
		} else {
			previous_space = false
			previous_break = false
		}

		// [Go]: Why 'z'? Couldn't be the end of the string as that's the loop condition.
		preceeded_by_whitespace = is_blankz(value, i)
	}

	emitter.scalar_data.multiline = line_breaks
	emitter.scalar_data.flow_plain_allowed = true
	emitter.scalar_data.block_plain_allowed = true
	emitter.scalar_data.single_quoted_allowed = true
	emitter.scalar_data.block_allowed = true

	if leading_space || leading_break || trailing_space || trailing_break {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
	}
	if trailing_space {
		emitter.scalar_data.block_allowed = false
	}
	if break_space {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
		emitter.scalar_data.single_quoted_allowed = false
	}
	if space_break || special_characters {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
		emitter.scalar_data.single_quoted_allowed = false
		emitter.scalar_data.block_allowed = false
	}
	if line_breaks {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
	}
	if flow_indicators {
		emitter.scalar_data.flow_plain_allowed = false
	}
	if block_indicators {
		emitter.scalar_data.block_plain_allowed = false
	}
	return true
}

// Check if the event data is valid.
func yaml_emitter_analyze_event(emitter *yaml_emitter_t, event *yaml_event_t) bool {

	emitter.anchor_data.anchor = nil
	emitter.tag_data.handle = nil
	emitter.tag_data.suffix = nil
	emitter.scalar_data.value = nil

	switch event.typ {
	case yaml_ALIAS_EVENT:
		if !yaml_emitter_analyze_anchor(emitter, event.anchor, true) {
			return false
		}

	case yaml_SCALAR_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter, event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical || (!event.implicit && !event.quoted_implicit)) {
			if !yaml_emitter_analyze_tag(emitter, event.tag) {
				return false
			}
		}
		if !yaml_emitter_analyze_scalar(emitter, event.value) {
			return false
		}

	case yaml_SEQUENCE_START_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter, event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical || !event.implicit) {
			if !yaml_emitter_analyze_tag(emitter, event.tag) {
				return false
			}
		}

	case yaml_MAPPING_START_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter, event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical || !event.implicit) {
			if !yaml_emitter_analyze_tag(emitter, event.tag) {
				return false
			}
		}
	}
	return true
}