diff options
Diffstat (limited to 'src/lib-mail/mail-html2text.c')
| -rw-r--r-- | src/lib-mail/mail-html2text.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/src/lib-mail/mail-html2text.c b/src/lib-mail/mail-html2text.c new file mode 100644 index 0000000..9332b64 --- /dev/null +++ b/src/lib-mail/mail-html2text.c @@ -0,0 +1,354 @@ +/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */ + +#include "lib.h" +#include "buffer.h" +#include "unichar.h" +#include "message-parser.h" +#include "mail-html2text.h" + +/* Zero-width space (​) apparently also belongs here, but that gets a + bit tricky to handle.. is it actually used anywhere? */ +#define HTML_WHITESPACE(c) \ + ((c) == ' ' || (c) == '\t' || (c) == '\r' || (c) == '\n') + +enum html_state { + /* regular text */ + HTML_STATE_TEXT, + /* tag outside "quoted string" */ + HTML_STATE_TAG, + /* tag inside "double quoted string" */ + HTML_STATE_TAG_DQUOTED, + /* tag -> "escape\ */ + HTML_STATE_TAG_DQUOTED_ESCAPE, + /* tag inside 'single quoted string' */ + HTML_STATE_TAG_SQUOTED, + /* tag -> 'escape\ */ + HTML_STATE_TAG_SQUOTED_ESCAPE, + /* comment */ + HTML_STATE_COMMENT, + /* comment is ending, we've seen "--" and now just waiting for ">" */ + HTML_STATE_COMMENT_END, + /* (java)script */ + HTML_STATE_SCRIPT, + /* CSS style */ + HTML_STATE_STYLE, + /* <![CDATA[...]]> */ + HTML_STATE_CDATA +}; + +struct mail_html2text { + enum mail_html2text_flags flags; + enum html_state state; + buffer_t *input; + unsigned int quote_level; + bool add_newline; +}; + +static struct { + const char *name; + unichar_t chr; +} html_entities[] = { +#include "html-entities.h" +}; + +struct mail_html2text * +mail_html2text_init(enum mail_html2text_flags flags) +{ + struct mail_html2text *ht; + + ht = i_new(struct mail_html2text, 1); + ht->flags = flags; + ht->input = buffer_create_dynamic(default_pool, 512); + return ht; +} + +static size_t +parse_tag_name(struct mail_html2text *ht, + const unsigned char *data, size_t size) +{ + size_t i; + + if (size >= 3 && memcmp(data, "!--", 3) == 0) { + ht->state = HTML_STATE_COMMENT; + return 3 + 1; + } + if (size >= 7 && i_memcasecmp(data, "script", 6) == 0 && + (HTML_WHITESPACE(data[6]) || data[6] == '>')) { + ht->state = HTML_STATE_SCRIPT; + return 7 + 1; + } + if (size >= 6 && i_memcasecmp(data, "style", 5) == 0 && + (HTML_WHITESPACE(data[5]) || data[5] == '>')) { + ht->state = HTML_STATE_STYLE; + return 6 + 1; + } + if (size >= 8 && i_memcasecmp(data, "![CDATA[", 8) == 0) { + ht->state = HTML_STATE_CDATA; + return 8 + 1; + } + + if (size >= 11 && i_memcasecmp(data, "blockquote", 10) == 0 && + (HTML_WHITESPACE(data[10]) || data[10] == '>')) { + ht->quote_level++; + ht->state = HTML_STATE_TAG; + return 1; + } else if (ht->quote_level > 0 && + size >= 12 && i_memcasecmp(data, "/blockquote>", 12) == 0) { + ht->quote_level--; + if ((ht->flags & MAIL_HTML2TEXT_FLAG_SKIP_QUOTED) == 0) + ht->add_newline = TRUE; + ht->state = HTML_STATE_TAG; + return 1; + } + if (size < 12) { + /* can we see the whole tag name? */ + for (i = 0; i < size; i++) { + if (HTML_WHITESPACE(data[i]) || data[i] == '>') + break; + } + if (i == size) { + /* need more data */ + return 0; + } + } + ht->state = HTML_STATE_TAG; + return 1; +} + +static bool html_entity_get_unichar(const char *name, unichar_t *chr_r) +{ + unichar_t chr; + + for (size_t i = 0; i < N_ELEMENTS(html_entities); i++) { + if (strcmp(html_entities[i].name, name) == 0) { + *chr_r = html_entities[i].chr; + return TRUE; + } + } + + /* maybe it's just encoded binary byte + it can be &#nnn; or &#xnnn; + */ + if (name[0] == '#' && + ((name[1] == 'x' && + str_to_uint32_hex(name+2, &chr) == 0) || + str_to_uint32(name+1, &chr) == 0) && + uni_is_valid_ucs4(chr)) { + *chr_r = chr; + return TRUE; + } + + return FALSE; +} + +static size_t parse_entity(const unsigned char *data, size_t size, + buffer_t *output) +{ + char entity[10]; + unichar_t chr; + size_t i; + + for (i = 0; i < size; i++) { + if (HTML_WHITESPACE(data[i]) || i >= sizeof(entity)) { + /* broken entity */ + return 1; + } + if (data[i] == ';') + break; + } + if (i == size) + return 0; + + i_assert(i < sizeof(entity)); + memcpy(entity, data, i); entity[i] = '\0'; + + if (html_entity_get_unichar(entity, &chr)) + uni_ucs4_to_utf8_c(chr, output); + return i + 1 + 1; +} + +static void mail_html2text_add_space(buffer_t *output) +{ + const unsigned char *data = output->data; + + if (output->used > 0 && data[output->used-1] != ' ' && + data[output->used-1] != '\n') + buffer_append_c(output, ' '); +} + +static size_t +parse_data(struct mail_html2text *ht, + const unsigned char *data, size_t size, buffer_t *output) +{ + size_t i, ret; + + for (i = 0; i < size; i++) { + unsigned char c = data[i]; + + switch (ht->state) { + case HTML_STATE_TEXT: + if (c == '<') { + ret = parse_tag_name(ht, data+i+1, size-i-1); + if (ret == 0) + return i; + i += ret - 1; + } else if (ht->quote_level > 0 && + (ht->flags & MAIL_HTML2TEXT_FLAG_SKIP_QUOTED) != 0) { + break; + } else if (c == '&') { + ret = parse_entity(data+i+1, size-i-1, output); + if (ret == 0) + return i; + i += ret - 1; + } else { + buffer_append_c(output, c); + } + break; + case HTML_STATE_TAG: + if (c == '"') + ht->state = HTML_STATE_TAG_DQUOTED; + else if (c == '\'') + ht->state = HTML_STATE_TAG_SQUOTED; + else if (c == '>') { + ht->state = HTML_STATE_TEXT; + if (ht->quote_level > 0 && + (ht->flags & MAIL_HTML2TEXT_FLAG_SKIP_QUOTED) == 0) { + buffer_append(output, "\n>", 2); + } else if (ht->add_newline) { + buffer_append_c(output, '\n'); + } + ht->add_newline = FALSE; + mail_html2text_add_space(output); + } + break; + case HTML_STATE_TAG_DQUOTED: + if (c == '"') + ht->state = HTML_STATE_TAG; + else if (c == '\\') + ht->state = HTML_STATE_TAG_DQUOTED_ESCAPE; + break; + case HTML_STATE_TAG_DQUOTED_ESCAPE: + ht->state = HTML_STATE_TAG_DQUOTED; + break; + case HTML_STATE_TAG_SQUOTED: + if (c == '\'') + ht->state = HTML_STATE_TAG; + else if (c == '\\') + ht->state = HTML_STATE_TAG_SQUOTED_ESCAPE; + break; + case HTML_STATE_TAG_SQUOTED_ESCAPE: + ht->state = HTML_STATE_TAG_SQUOTED; + break; + case HTML_STATE_COMMENT: + if (c == '-') { + if (i+1 == size) + return i; + if (data[i+1] == '-') { + ht->state = HTML_STATE_COMMENT_END; + i++; + } + } + break; + case HTML_STATE_COMMENT_END: + if (c == '>') + ht->state = HTML_STATE_TEXT; + else if (!HTML_WHITESPACE(c)) + ht->state = HTML_STATE_COMMENT; + break; + case HTML_STATE_SCRIPT: + if (c == '<') { + unsigned int max_len = I_MIN(size-i, 9); + + if (i_memcasecmp(data+i, "</script>", max_len) == 0) { + if (max_len < 9) + return i; + mail_html2text_add_space(output); + ht->state = HTML_STATE_TEXT; + i += 8; + } + } + break; + case HTML_STATE_STYLE: + if (c == '<') { + unsigned int max_len = I_MIN(size-i, 8); + + if (i_memcasecmp(data+i, "</style>", max_len) == 0) { + if (max_len < 8) + return i; + mail_html2text_add_space(output); + ht->state = HTML_STATE_TEXT; + i += 7; + } + } + break; + case HTML_STATE_CDATA: + if (c == ']') { + unsigned int max_len = I_MIN(size-i, 3); + + if (i_memcasecmp(data+i, "]]>", max_len) == 0) { + if (max_len < 3) + return i; + ht->state = HTML_STATE_TEXT; + i += 2; + break; + } + } + if (ht->quote_level == 0 || + (ht->flags & MAIL_HTML2TEXT_FLAG_SKIP_QUOTED) == 0) + buffer_append_c(output, c); + break; + } + } + return i; +} + +void mail_html2text_more(struct mail_html2text *ht, + const unsigned char *data, size_t size, + buffer_t *output) +{ + size_t pos, inc_size, buf_orig_size; + + i_assert(size > 0); + + while (ht->input->used > 0) { + /* we didn't get enough input the last time to know + what to do. */ + buf_orig_size = ht->input->used; + + inc_size = I_MIN(size, 128); + buffer_append(ht->input, data, inc_size); + pos = parse_data(ht, ht->input->data, + ht->input->used, output); + if (pos == 0) { + /* we need to add more data into buffer */ + data += inc_size; + size -= inc_size; + if (size == 0) + return; + } else if (pos >= buf_orig_size) { + /* we parsed forward */ + data += pos - buf_orig_size; + size -= pos - buf_orig_size; + buffer_set_used_size(ht->input, 0); + } else { + /* invalid input - eat away what we parsed so far + and retry */ + buffer_set_used_size(ht->input, buf_orig_size); + buffer_delete(ht->input, 0, pos); + } + } + pos = parse_data(ht, data, size, output); + buffer_append(ht->input, data + pos, size - pos); +} + +void mail_html2text_deinit(struct mail_html2text **_ht) +{ + struct mail_html2text *ht = *_ht; + + if (ht == NULL) + return; + + *_ht = NULL; + buffer_free(&ht->input); + i_free(ht); +} |