nostrdb/add initial content parser

Signed-off-by: William Casarin <jb55@jb55.com>

nostrdb/src/content_parser.c

@@ -0,0 +1,388 @@
+#include "damus.h"
+#include "cursor.h"
+#include "bolt11.h"
+#include "bech32.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include "cursor.h"
+
+static int parse_digit(struct cursor *cur, int *digit) {
+	int c;
+	if ((c = peek_char(cur, 0)) == -1)
+		return 0;
+	
+	c -= '0';
+	
+	if (c >= 0 && c <= 9) {
+		*digit = c;
+		cur->p++;
+		return 1;
+	}
+	return 0;
+}
+
+
+static int parse_mention_index(struct cursor *cur, struct note_block *block) {
+	int d1, d2, d3, ind;
+	u8 *start = cur->p;
+	
+	if (!parse_str(cur, "#["))
+		return 0;
+	
+	if (!parse_digit(cur, &d1)) {
+		cur->p = start;
+		return 0;
+	}
+	
+	ind = d1;
+	
+	if (parse_digit(cur, &d2))
+		ind = (d1 * 10) + d2;
+	
+	if (parse_digit(cur, &d3))
+		ind = (d1 * 100) + (d2 * 10) + d3;
+	
+	if (!parse_char(cur, ']')) {
+		cur->p = start;
+		return 0;
+	}
+	
+	block->type = BLOCK_MENTION_INDEX;
+	block->block.mention_index = ind;
+	
+	return 1;
+}
+
+static int parse_hashtag(struct cursor *cur, struct note_block *block) {
+	int c;
+	u8 *start = cur->p;
+	
+	if (!parse_char(cur, '#'))
+		return 0;
+	
+	c = peek_char(cur, 0);
+	if (c == -1 || is_whitespace(c) || c == '#') {
+		cur->p = start;
+		return 0;
+	}
+	
+	consume_until_boundary(cur);
+	
+	block->type = BLOCK_HASHTAG;
+	block->block.str.start = (const char*)(start + 1);
+	block->block.str.end = (const char*)cur->p;
+	
+	return 1;
+}
+
+static int add_block(struct note_blocks *blocks, struct note_block block)
+{
+	if (blocks->num_blocks + 1 >= MAX_BLOCKS)
+		return 0;
+	
+	blocks->blocks[blocks->num_blocks++] = block;
+	return 1;
+}
+
+static int add_text_block(struct note_blocks *blocks, const u8 *start, const u8 *end)
+{
+	struct note_block b;
+	
+	if (start == end)
+		return 1;
+	
+	b.type = BLOCK_TEXT;
+	b.block.str.start = (const char*)start;
+	b.block.str.end = (const char*)end;
+	
+	return add_block(blocks, b);
+}
+
+static int consume_url_fragment(struct cursor *cur)
+{
+	int c;
+
+	if ((c = peek_char(cur, 0)) < 0)
+		return 1;
+
+	if (c != '#' && c != '?') {
+		return 1;
+	}
+
+	cur->p++;
+
+	return consume_until_whitespace(cur, 1);
+}
+
+static int consume_url_path(struct cursor *cur)
+{
+	int c;
+
+	if ((c = peek_char(cur, 0)) < 0)
+		return 1;
+
+	if (c != '/') {
+		return 1;
+	}
+
+	while (cur->p < cur->end) {
+		c = *cur->p;
+
+		if (c == '?' || c == '#' || is_whitespace(c)) {
+			return 1;
+		}
+
+		cur->p++;
+	}
+
+	return 1;
+}
+
+static int consume_url_host(struct cursor *cur)
+{
+	char c;
+	int count = 0;
+
+	while (cur->p < cur->end) {
+		c = *cur->p;
+		// TODO: handle IDNs
+		if (is_alphanumeric(c) || c == '.' || c == '-')
+		{
+			count++;
+			cur->p++;
+			continue;
+		}
+
+		return count != 0;
+	}
+
+
+	// this means the end of the URL hostname is the end of the buffer and we finished
+	return count != 0;
+}
+
+static int parse_url(struct cursor *cur, struct note_block *block) {
+	u8 *start = cur->p;
+	u8 *host;
+	int host_len;
+	struct cursor path_cur;
+	
+	if (!parse_str(cur, "http"))
+		return 0;
+	
+	if (parse_char(cur, 's') || parse_char(cur, 'S')) {
+		if (!parse_str(cur, "://")) {
+			cur->p = start;
+			return 0;
+		}
+	} else {
+		if (!parse_str(cur, "://")) {
+			cur->p = start;
+			return 0;
+		}
+	}
+
+	// make sure to save the hostname. We will use this to detect damus.io links
+	host = cur->p;
+
+	if (!consume_url_host(cur)) {
+		cur->p = start;
+		return 0;
+	}
+
+	// get the length of the host string
+	host_len = (int)(cur->p - host);
+
+	// save the current parse state so that we can continue from here when
+	// parsing the bech32 in the damus.io link if we have it
+	copy_cursor(cur, &path_cur);
+
+	// skip leading /
+	cursor_skip(&path_cur, 1);
+
+	if (!consume_url_path(cur)) {
+		cur->p = start;
+		return 0;
+	}
+
+	if (!consume_url_fragment(cur)) {
+		cur->p = start;
+		return 0;
+	}
+
+	// smart parens
+	if (start - 1 >= 0 &&
+		start < cur->end &&
+		*(start - 1) == '(' &&
+		(cur->p - 1) < cur->end &&
+		*(cur->p - 1) == ')')
+	{
+		cur->p--;
+	}
+
+	// save the bech32 string pos in case we hit a damus.io link
+	block->block.str.start = (const char *)path_cur.p;
+
+	// if we have a damus link, make it a mention
+	if (host_len == 8
+	&& !strncmp((const char *)host, "damus.io", 8)
+	&& parse_nostr_bech32(&path_cur, &block->block.mention_bech32.bech32))
+	{
+		block->block.str.end = (const char *)path_cur.p;
+		block->type = BLOCK_MENTION_BECH32;
+		return 1;
+	}
+
+	block->type = BLOCK_URL;
+	block->block.str.start = (const char *)start;
+	block->block.str.end = (const char *)cur->p;
+	
+	return 1;
+}
+
+static int parse_invoice(struct cursor *cur, struct note_block *block) {
+	u8 *start, *end;
+	char *fail;
+	struct bolt11 *bolt11;
+	// optional
+	parse_str(cur, "lightning:");
+	
+	start = cur->p;
+	
+	if (!parse_str(cur, "lnbc"))
+		return 0;
+	
+	if (!consume_until_whitespace(cur, 1)) {
+		cur->p = start;
+		return 0;
+	}
+	
+	end = cur->p;
+	
+	char str[end - start + 1];
+	str[end - start] = 0;
+	memcpy(str, start, end - start);
+	
+	if (!(bolt11 = bolt11_decode(NULL, str, &fail))) {
+		cur->p = start;
+		return 0;
+	}
+	
+	block->type = BLOCK_INVOICE;
+	
+	block->block.invoice.invstr.start = (const char*)start;
+	block->block.invoice.invstr.end = (const char*)end;
+	block->block.invoice.bolt11 = bolt11;
+	
+	cur->p = end;
+	
+	return 1;
+}
+
+
+static int parse_mention_bech32(struct cursor *cur, struct note_block *block) {
+	u8 *start = cur->p;
+	
+	parse_char(cur, '@');
+	parse_str(cur, "nostr:");
+
+	block->block.str.start = (const char *)cur->p;
+	
+	if (!parse_nostr_bech32(cur, &block->block.mention_bech32.bech32)) {
+		cur->p = start;
+		return 0;
+	}
+	
+	block->block.str.end = (const char *)cur->p;
+	
+	block->type = BLOCK_MENTION_BECH32;
+
+	return 1;
+}
+
+static int add_text_then_block(struct cursor *cur, struct note_blocks *blocks, struct note_block block, u8 **start, const u8 *pre_mention)
+{
+	if (!add_text_block(blocks, *start, pre_mention))
+		return 0;
+	
+	*start = (u8*)cur->p;
+	
+	if (!add_block(blocks, block))
+		return 0;
+	
+	return 1;
+}
+
+int ndb_parse_content(struct note_blocks *blocks, const char *content) {
+	int cp, c;
+	struct cursor cur;
+	struct note_block block;
+	u8 *start, *pre_mention;
+	
+	blocks->words = 0;
+	blocks->num_blocks = 0;
+	make_cursor((u8*)content, (u8*)content + strlen(content), &cur);
+	
+	start = cur.p;
+	while (cur.p < cur.end && blocks->num_blocks < MAX_BLOCKS) {
+		cp = peek_char(&cur, -1);
+		c  = peek_char(&cur, 0);
+		
+		// new word
+		if (is_whitespace(cp) && !is_whitespace(c)) {
+			blocks->words++;
+		}
+		
+		pre_mention = cur.p;
+		if (cp == -1 || is_left_boundary(cp) || c == '#') {
+			if (c == '#' && (parse_mention_index(&cur, &block) || parse_hashtag(&cur, &block))) {
+				if (!add_text_then_block(&cur, blocks, block, &start, pre_mention))
+					return 0;
+				continue;
+			} else if ((c == 'h' || c == 'H') && parse_url(&cur, &block)) {
+				if (!add_text_then_block(&cur, blocks, block, &start, pre_mention))
+					return 0;
+				continue;
+			} else if ((c == 'l' || c == 'L') && parse_invoice(&cur, &block)) {
+				if (!add_text_then_block(&cur, blocks, block, &start, pre_mention))
+					return 0;
+				continue;
+			} else if ((c == 'n' || c == '@') && parse_mention_bech32(&cur, &block)) {
+				if (!add_text_then_block(&cur, blocks, block, &start, pre_mention))
+					return 0;
+				continue;
+			}
+		}
+		
+		cur.p++;
+	}
+	
+	if (cur.p - start > 0) {
+		if (!add_text_block(blocks, start, cur.p))
+			return 0;
+	}
+	
+	return 1;
+}
+
+void blocks_init(struct note_blocks *blocks) {
+	blocks->blocks = malloc(sizeof(struct note_block) * MAX_BLOCKS);
+	blocks->num_blocks = 0;
+}
+
+void blocks_free(struct note_blocks *blocks) {
+	if (!blocks->blocks) {
+		return;
+	}
+	
+	for (int i = 0; i < blocks->num_blocks; ++i) {
+		if (blocks->blocks[i].type == BLOCK_MENTION_BECH32) {
+			free(blocks->blocks[i].block.mention_bech32.bech32.buffer);
+			blocks->blocks[i].block.mention_bech32.bech32.buffer = NULL;
+		}
+	}
+
+	free(blocks->blocks);
+	blocks->num_blocks = 0;
+}