chore: import upstream snapshot with attribution

internal/cbm/vendored/grammars/javascript/scanner.c

@@ -0,0 +1,364 @@
+#include "tree_sitter/parser.h"
+
+#include <stdio.h>
+#include <wctype.h>
+
+enum TokenType {
+    AUTOMATIC_SEMICOLON,
+    TEMPLATE_CHARS,
+    TERNARY_QMARK,
+    HTML_COMMENT,
+    LOGICAL_OR,
+    ESCAPE_SEQUENCE,
+    REGEX_PATTERN,
+    JSX_TEXT,
+};
+
+void *tree_sitter_javascript_external_scanner_create() { return NULL; }
+
+void tree_sitter_javascript_external_scanner_destroy(void *p) {}
+
+unsigned tree_sitter_javascript_external_scanner_serialize(void *payload, char *buffer) { return 0; }
+
+void tree_sitter_javascript_external_scanner_deserialize(void *p, const char *b, unsigned n) {}
+
+static inline void advance(TSLexer *lexer) { lexer->advance(lexer, false); }
+
+static inline void skip(TSLexer *lexer) { lexer->advance(lexer, true); }
+
+static bool scan_template_chars(TSLexer *lexer) {
+    lexer->result_symbol = TEMPLATE_CHARS;
+    for (bool has_content = false;; has_content = true) {
+        lexer->mark_end(lexer);
+        switch (lexer->lookahead) {
+            case '`':
+                return has_content;
+            case '\0':
+                return false;
+            case '$':
+                advance(lexer);
+                if (lexer->lookahead == '{') {
+                    return has_content;
+                }
+                break;
+            case '\\':
+                return has_content;
+            default:
+                advance(lexer);
+        }
+    }
+}
+
+typedef enum {
+    REJECT,     // Semicolon is illegal, ie a syntax error occurred
+    NO_NEWLINE, // Unclear if semicolon will be legal, continue
+    ACCEPT,     // Semicolon is legal, assuming a comment was encountered
+} WhitespaceResult;
+
+/**
+ * @param consume If false, only consume enough to check if comment indicates semicolon-legality
+ */
+static WhitespaceResult scan_whitespace_and_comments(TSLexer *lexer, bool *scanned_comment, bool consume) {
+    bool saw_block_newline = false;
+
+    for (;;) {
+        while (iswspace(lexer->lookahead)) {
+            skip(lexer);
+        }
+
+        if (lexer->lookahead == '/') {
+            skip(lexer);
+
+            if (lexer->lookahead == '/') {
+                skip(lexer);
+                while (lexer->lookahead != 0 && lexer->lookahead != '\n' && lexer->lookahead != 0x2028 &&
+                       lexer->lookahead != 0x2029) {
+                    skip(lexer);
+                }
+                *scanned_comment = true;
+            } else if (lexer->lookahead == '*') {
+                skip(lexer);
+                while (lexer->lookahead != 0) {
+                    if (lexer->lookahead == '*') {
+                        skip(lexer);
+                        if (lexer->lookahead == '/') {
+                            skip(lexer);
+                            *scanned_comment = true;
+
+                            if (lexer->lookahead != '/' && !consume) {
+                                return saw_block_newline ? ACCEPT : NO_NEWLINE;
+                            }
+
+                            break;
+                        }
+                    } else if (lexer->lookahead == '\n' || lexer->lookahead == 0x2028 || lexer->lookahead == 0x2029) {
+                        saw_block_newline = true;
+                        skip(lexer);
+                    } else {
+                        skip(lexer);
+                    }
+                }
+            } else {
+                return REJECT;
+            }
+        } else {
+            return ACCEPT;
+        }
+    }
+}
+
+static bool scan_automatic_semicolon(TSLexer *lexer, bool comment_condition, bool *scanned_comment) {
+    lexer->result_symbol = AUTOMATIC_SEMICOLON;
+    lexer->mark_end(lexer);
+
+    for (;;) {
+        if (lexer->lookahead == 0) {
+            return true;
+        }
+
+        if (lexer->lookahead == '/') {
+            WhitespaceResult result = scan_whitespace_and_comments(lexer, scanned_comment, false);
+            if (result == REJECT) {
+                return false;
+            }
+
+            if (result == ACCEPT && comment_condition && lexer->lookahead != ',' && lexer->lookahead != '=') {
+                return true;
+            }
+        }
+
+        if (lexer->lookahead == '}') {
+            return true;
+        }
+
+        if (lexer->is_at_included_range_start(lexer)) {
+            return true;
+        }
+
+        if (lexer->lookahead == '\n' || lexer->lookahead == 0x2028 || lexer->lookahead == 0x2029) {
+            break;
+        }
+
+        if (!iswspace(lexer->lookahead)) {
+            return false;
+        }
+
+        skip(lexer);
+    }
+
+    skip(lexer);
+
+    if (scan_whitespace_and_comments(lexer, scanned_comment, true) == REJECT) {
+        return false;
+    }
+
+    switch (lexer->lookahead) {
+        case '`':
+        case ',':
+        case ':':
+        case ';':
+        case '*':
+        case '%':
+        case '>':
+        case '<':
+        case '=':
+        case '[':
+        case '(':
+        case '?':
+        case '^':
+        case '|':
+        case '&':
+        case '/':
+            return false;
+
+        // Insert a semicolon before decimals literals but not otherwise.
+        case '.':
+            skip(lexer);
+            return iswdigit(lexer->lookahead);
+
+        // Insert a semicolon before `--` and `++`, but not before binary `+` or `-`.
+        case '+':
+            skip(lexer);
+            return lexer->lookahead == '+';
+        case '-':
+            skip(lexer);
+            return lexer->lookahead == '-';
+
+        // Don't insert a semicolon before `!=`, but do insert one before a unary `!`.
+        case '!':
+            skip(lexer);
+            return lexer->lookahead != '=';
+
+        // Don't insert a semicolon before `in` or `instanceof`, but do insert one
+        // before an identifier.
+        case 'i':
+            skip(lexer);
+
+            if (lexer->lookahead != 'n') {
+                return true;
+            }
+            skip(lexer);
+
+            if (!iswalpha(lexer->lookahead)) {
+                return false;
+            }
+
+            for (unsigned i = 0; i < 8; i++) {
+                if (lexer->lookahead != "stanceof"[i]) {
+                    return true;
+                }
+                skip(lexer);
+            }
+
+            if (!iswalpha(lexer->lookahead)) {
+                return false;
+            }
+            break;
+
+        default:
+            break;
+    }
+
+    return true;
+}
+
+static bool scan_ternary_qmark(TSLexer *lexer) {
+    for (;;) {
+        if (!iswspace(lexer->lookahead)) {
+            break;
+        }
+        skip(lexer);
+    }
+
+    if (lexer->lookahead == '?') {
+        advance(lexer);
+
+        if (lexer->lookahead == '?') {
+            return false;
+        }
+
+        lexer->mark_end(lexer);
+        lexer->result_symbol = TERNARY_QMARK;
+
+        if (lexer->lookahead == '.') {
+            advance(lexer);
+            if (iswdigit(lexer->lookahead)) {
+                return true;
+            }
+            return false;
+        }
+        return true;
+    }
+    return false;
+}
+
+static bool scan_html_comment(TSLexer *lexer) {
+    while (iswspace(lexer->lookahead) || lexer->lookahead == 0x2028 || lexer->lookahead == 0x2029) {
+        skip(lexer);
+    }
+
+    const char *comment_start = "<!--";
+    const char *comment_end = "-->";
+
+    if (lexer->lookahead == '<') {
+        for (unsigned i = 0; i < 4; i++) {
+            if (lexer->lookahead != comment_start[i]) {
+                return false;
+            }
+            advance(lexer);
+        }
+    } else if (lexer->lookahead == '-') {
+        for (unsigned i = 0; i < 3; i++) {
+            if (lexer->lookahead != comment_end[i]) {
+                return false;
+            }
+            advance(lexer);
+        }
+    } else {
+        return false;
+    }
+
+    while (lexer->lookahead != 0 && lexer->lookahead != '\n' && lexer->lookahead != 0x2028 &&
+           lexer->lookahead != 0x2029) {
+        advance(lexer);
+    }
+
+    lexer->result_symbol = HTML_COMMENT;
+    lexer->mark_end(lexer);
+
+    return true;
+}
+
+static bool scan_jsx_text(TSLexer *lexer) {
+    // saw_text will be true if we see any non-whitespace content, or any whitespace content that is not a newline and
+    // does not immediately follow a newline.
+    bool saw_text = false;
+    // at_newline will be true if we are currently at a newline, or if we are at whitespace that is not a newline but
+    // immediately follows a newline.
+    bool at_newline = false;
+
+    while (lexer->lookahead != 0 && lexer->lookahead != '<' && lexer->lookahead != '>' && lexer->lookahead != '{' &&
+           lexer->lookahead != '}' && lexer->lookahead != '&') {
+        bool is_wspace = iswspace(lexer->lookahead);
+        if (lexer->lookahead == '\n') {
+            at_newline = true;
+        } else {
+            // If at_newline is already true, and we see some whitespace, then it must stay true.
+            // Otherwise, it should be false.
+            //
+            // See the table below to determine the logic for computing `saw_text`.
+            //
+            // |------------------------------------|
+            // | at_newline | is_wspace | saw_text  |
+            // |------------|-----------|-----------|
+            // | false (0)  | false (0) | true  (1) |
+            // | false (0)  | true  (1) | true  (1) |
+            // | true  (1)  | false (0) | true  (1) |
+            // | true  (1)  | true  (1) | false (0) |
+            // |------------------------------------|
+
+            at_newline &= is_wspace;
+            if (!at_newline) {
+                saw_text = true;
+            }
+        }
+
+        advance(lexer);
+    }
+
+    lexer->result_symbol = JSX_TEXT;
+    return saw_text;
+}
+
+bool tree_sitter_javascript_external_scanner_scan(void *payload, TSLexer *lexer, const bool *valid_symbols) {
+    if (valid_symbols[TEMPLATE_CHARS]) {
+        if (valid_symbols[AUTOMATIC_SEMICOLON]) {
+            return false;
+        }
+        return scan_template_chars(lexer);
+    }
+
+    if (valid_symbols[JSX_TEXT] && scan_jsx_text(lexer)) {
+        return true;
+    }
+
+    if (valid_symbols[AUTOMATIC_SEMICOLON]) {
+        bool scanned_comment = false;
+        bool ret = scan_automatic_semicolon(lexer, !valid_symbols[LOGICAL_OR], &scanned_comment);
+        if (!ret && !scanned_comment && valid_symbols[TERNARY_QMARK] && lexer->lookahead == '?') {
+            return scan_ternary_qmark(lexer);
+        }
+        return ret;
+    }
+
+    if (valid_symbols[TERNARY_QMARK]) {
+        return scan_ternary_qmark(lexer);
+    }
+
+    if (valid_symbols[HTML_COMMENT] && !valid_symbols[LOGICAL_OR] && !valid_symbols[ESCAPE_SEQUENCE] &&
+        !valid_symbols[REGEX_PATTERN]) {
+        return scan_html_comment(lexer);
+    }
+
+    return false;
+}