python/Lib/site-packages/markdown_it/rules_block/blockquote.py

# Block quotes
from __future__ import annotations

import logging

from ..common.utils import isStrSpace
from .state_block import StateBlock

LOGGER = logging.getLogger(__name__)


def blockquote(state: StateBlock, startLine: int, endLine: int, silent: bool) -> bool:
    LOGGER.debug(
        "entering blockquote: %s, %s, %s, %s", state, startLine, endLine, silent
    )

    oldLineMax = state.lineMax
    pos = state.bMarks[startLine] + state.tShift[startLine]
    max = state.eMarks[startLine]

    if state.is_code_block(startLine):
        return False

    # check the block quote marker
    try:
        if state.src[pos] != ">":
            return False
    except IndexError:
        return False
    pos += 1

    # we know that it's going to be a valid blockquote,
    # so no point trying to find the end of it in silent mode
    if silent:
        return True

    # set offset past spaces and ">"
    initial = offset = state.sCount[startLine] + 1

    try:
        second_char: str | None = state.src[pos]
    except IndexError:
        second_char = None

    # skip one optional space after '>'
    if second_char == " ":
        # ' >   test '
        #     ^ -- position start of line here:
        pos += 1
        initial += 1
        offset += 1
        adjustTab = False
        spaceAfterMarker = True
    elif second_char == "\t":
        spaceAfterMarker = True

        if (state.bsCount[startLine] + offset) % 4 == 3:
            # '  >\t  test '
            #       ^ -- position start of line here (tab has width==1)
            pos += 1
            initial += 1
            offset += 1
            adjustTab = False
        else:
            # ' >\t  test '
            #    ^ -- position start of line here + shift bsCount slightly
            #         to make extra space appear
            adjustTab = True

    else:
        spaceAfterMarker = False

    oldBMarks = [state.bMarks[startLine]]
    state.bMarks[startLine] = pos

    while pos < max:
        ch = state.src[pos]

        if isStrSpace(ch):
            if ch == "\t":
                offset += (
                    4
                    - (offset + state.bsCount[startLine] + (1 if adjustTab else 0)) % 4
                )
            else:
                offset += 1

        else:
            break

        pos += 1

    oldBSCount = [state.bsCount[startLine]]
    state.bsCount[startLine] = (
        state.sCount[startLine] + 1 + (1 if spaceAfterMarker else 0)
    )

    lastLineEmpty = pos >= max

    oldSCount = [state.sCount[startLine]]
    state.sCount[startLine] = offset - initial

    oldTShift = [state.tShift[startLine]]
    state.tShift[startLine] = pos - state.bMarks[startLine]

    terminatorRules = state.md.block.ruler.getRules("blockquote")

    oldParentType = state.parentType
    state.parentType = "blockquote"

    # Search the end of the block
    #
    # Block ends with either:
    #  1. an empty line outside:
    #     ```
    #     > test
    #
    #     ```
    #  2. an empty line inside:
    #     ```
    #     >
    #     test
    #     ```
    #  3. another tag:
    #     ```
    #     > test
    #      - - -
    #     ```

    # for (nextLine = startLine + 1; nextLine < endLine; nextLine++) {
    nextLine = startLine + 1
    while nextLine < endLine:
        # check if it's outdented, i.e. it's inside list item and indented
        # less than said list item:
        #
        # ```
        # 1. anything
        #    > current blockquote
        # 2. checking this line
        # ```
        isOutdented = state.sCount[nextLine] < state.blkIndent

        pos = state.bMarks[nextLine] + state.tShift[nextLine]
        max = state.eMarks[nextLine]

        if pos >= max:
            # Case 1: line is not inside the blockquote, and this line is empty.
            break

        evaluatesTrue = state.src[pos] == ">" and not isOutdented
        pos += 1
        if evaluatesTrue:
            # This line is inside the blockquote.

            # set offset past spaces and ">"
            initial = offset = state.sCount[nextLine] + 1

            try:
                next_char: str | None = state.src[pos]
            except IndexError:
                next_char = None

            # skip one optional space after '>'
            if next_char == " ":
                # ' >   test '
                #     ^ -- position start of line here:
                pos += 1
                initial += 1
                offset += 1
                adjustTab = False
                spaceAfterMarker = True
            elif next_char == "\t":
                spaceAfterMarker = True

                if (state.bsCount[nextLine] + offset) % 4 == 3:
                    # '  >\t  test '
                    #       ^ -- position start of line here (tab has width==1)
                    pos += 1
                    initial += 1
                    offset += 1
                    adjustTab = False
                else:
                    # ' >\t  test '
                    #    ^ -- position start of line here + shift bsCount slightly
                    #         to make extra space appear
                    adjustTab = True

            else:
                spaceAfterMarker = False

            oldBMarks.append(state.bMarks[nextLine])
            state.bMarks[nextLine] = pos

            while pos < max:
                ch = state.src[pos]

                if isStrSpace(ch):
                    if ch == "\t":
                        offset += (
                            4
                            - (
                                offset
                                + state.bsCount[nextLine]
                                + (1 if adjustTab else 0)
                            )
                            % 4
                        )
                    else:
                        offset += 1
                else:
                    break

                pos += 1

            lastLineEmpty = pos >= max

            oldBSCount.append(state.bsCount[nextLine])
            state.bsCount[nextLine] = (
                state.sCount[nextLine] + 1 + (1 if spaceAfterMarker else 0)
            )

            oldSCount.append(state.sCount[nextLine])
            state.sCount[nextLine] = offset - initial

            oldTShift.append(state.tShift[nextLine])
            state.tShift[nextLine] = pos - state.bMarks[nextLine]

            nextLine += 1
            continue

        # Case 2: line is not inside the blockquote, and the last line was empty.
        if lastLineEmpty:
            break

        # Case 3: another tag found.
        terminate = False

        for terminatorRule in terminatorRules:
            if terminatorRule(state, nextLine, endLine, True):
                terminate = True
                break

        if terminate:
            # Quirk to enforce "hard termination mode" for paragraphs;
            # normally if you call `tokenize(state, startLine, nextLine)`,
            # paragraphs will look below nextLine for paragraph continuation,
            # but if blockquote is terminated by another tag, they shouldn't
            state.lineMax = nextLine

            if state.blkIndent != 0:
                # state.blkIndent was non-zero, we now set it to zero,
                # so we need to re-calculate all offsets to appear as
                # if indent wasn't changed
                oldBMarks.append(state.bMarks[nextLine])
                oldBSCount.append(state.bsCount[nextLine])
                oldTShift.append(state.tShift[nextLine])
                oldSCount.append(state.sCount[nextLine])
                state.sCount[nextLine] -= state.blkIndent

            break

        oldBMarks.append(state.bMarks[nextLine])
        oldBSCount.append(state.bsCount[nextLine])
        oldTShift.append(state.tShift[nextLine])
        oldSCount.append(state.sCount[nextLine])

        # A negative indentation means that this is a paragraph continuation
        #
        state.sCount[nextLine] = -1

        nextLine += 1

    oldIndent = state.blkIndent
    state.blkIndent = 0

    # Detect GitHub-style alert marker on the first content line.
    # Note: `startLine` here refers to the first content line of the
    # blockquote, after the `>` prefix has already been stripped by the
    # blockquote parser above (bMarks/tShift adjusted to skip `> `).
    alert_kind = None
    if state.md.options.get("alerts", False) and nextLine > startLine:
        alert_kind = _detect_alert(state, startLine)

    lines = [startLine, 0]

    if alert_kind is not None:
        # Emit alert tokens instead of blockquote tokens
        alert_lower = alert_kind.lower()
        token = state.push("alert_open", "div", 1)
        token.markup = ">"
        token.attrSet("class", f"markdown-alert markdown-alert-{alert_lower}")
        token.map = lines
        token.info = alert_kind
        token.meta = {"kind": alert_kind}

        # Emit a title paragraph: <p class="markdown-alert-title">Kind</p>
        token = state.push("alert_title_open", "p", 1)
        token.attrSet("class", "markdown-alert-title")
        title_token = state.push("inline", "", 0)
        title_token.content = alert_kind.capitalize()
        title_token.children = []
        token = state.push("alert_title_close", "p", -1)

        # Skip the marker line (startLine) and tokenize from startLine + 1.
        contentStart = startLine + 1
        if contentStart < nextLine:
            # tokenize() updates state.line to nextLine as part of its
            # contract, consistent with the blockquote code path below.
            state.md.block.tokenize(state, contentStart, nextLine)
        else:
            state.line = nextLine

        token = state.push("alert_close", "div", -1)
        token.markup = ">"
    else:
        token = state.push("blockquote_open", "blockquote", 1)
        token.markup = ">"
        token.map = lines

        state.md.block.tokenize(state, startLine, nextLine)

        token = state.push("blockquote_close", "blockquote", -1)
        token.markup = ">"

    state.lineMax = oldLineMax
    state.parentType = oldParentType
    # Update the opening token map for both alert and blockquote containers.
    lines[1] = state.line

    # Restore original tShift; this might not be necessary since the parser
    # has already been here, but just to make sure we can do that.
    for i, item in enumerate(oldTShift):
        state.bMarks[i + startLine] = oldBMarks[i]
        state.tShift[i + startLine] = item
        state.sCount[i + startLine] = oldSCount[i]
        state.bsCount[i + startLine] = oldBSCount[i]

    state.blkIndent = oldIndent

    return True


_ALERT_TYPES = {"NOTE", "TIP", "IMPORTANT", "WARNING", "CAUTION"}


def _detect_alert(state: StateBlock, startLine: int) -> str | None:
    """Detect ``[!TYPE]`` on *startLine* (after ``>`` prefix has been stripped).

    Returns the alert type string (e.g. ``"NOTE"``) or ``None``.
    """
    pos = state.bMarks[startLine] + state.tShift[startLine]
    maximum = state.eMarks[startLine]
    src = state.src

    # Trim trailing whitespace
    while maximum > pos and src[maximum - 1] in (" ", "\t"):
        maximum -= 1

    if maximum - pos < 4:
        return None
    if src[pos] != "[" or src[pos + 1] != "!":
        return None
    if src[maximum - 1] != "]":
        return None
    type_str = src[pos + 2 : maximum - 1].upper()
    if type_str not in _ALERT_TYPES:
        return None
    return type_str