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Diffstat (limited to '')
| -rw-r--r-- | src/lib-imap/imap-quote.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/src/lib-imap/imap-quote.c b/src/lib-imap/imap-quote.c new file mode 100644 index 0000000..622e21c --- /dev/null +++ b/src/lib-imap/imap-quote.c @@ -0,0 +1,239 @@ +/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */ + +#include "lib.h" +#include "str.h" +#include "imap-arg.h" +#include "imap-quote.h" + +/* If we have quoted-specials (<">, <\>) in a string, the minimum quoted-string + overhead is 3 bytes ("\") while the minimum literal overhead is 5 bytes + ("{n}\r\n"). But the literal overhead also depends on the string size. If + the string length is less than 10, literal catches up to quoted-string after + 3 quoted-specials. If the string length is 10..99, it catches up after 4 + quoted-specials, and so on. We'll assume that the string lengths are usually + in double digits, so we'll switch to literals after seeing 4 + quoted-specials. */ +#define QUOTED_MAX_ESCAPE_CHARS 4 + +void imap_append_string(string_t *dest, const char *src) +{ + i_assert(src != NULL); + + imap_append_nstring(dest, src); +} + +void imap_append_astring(string_t *dest, const char *src) +{ + unsigned int i; + + i_assert(src != NULL); + + for (i = 0; src[i] != '\0'; i++) { + if (!IS_ASTRING_CHAR(src[i])) { + imap_append_string(dest, src); + return; + } + } + /* don't mix up NIL and "NIL"! */ + if (i == 0 || strcasecmp(src, "NIL") == 0) + imap_append_string(dest, src); + else + str_append(dest, src); +} + +static void +imap_append_literal(string_t *dest, const char *src, unsigned int pos) +{ + size_t full_len = pos + strlen(src+pos); + + str_printfa(dest, "{%zu}\r\n", full_len); + buffer_append(dest, src, full_len); +} + +void imap_append_nstring(string_t *dest, const char *src) +{ + unsigned int escape_count = 0; + size_t i; + + if (src == NULL) { + str_append(dest, "NIL"); + return; + } + + /* first check if we can (or want to) write this as quoted or + as literal. + + quoted-specials = DQUOTE / "\" + QUOTED-CHAR = <any TEXT-CHAR except quoted-specials> / + "\" quoted-specials + TEXT-CHAR = <any CHAR except CR and LF> + */ + for (i = 0; src[i] != '\0'; i++) { + switch (src[i]) { + case '"': + case '\\': + if (escape_count++ < QUOTED_MAX_ESCAPE_CHARS) + break; + /* fall through */ + case 13: + case 10: + imap_append_literal(dest, src, i); + return; + default: + if ((unsigned char)src[i] >= 0x80) { + imap_append_literal(dest, src, i); + return; + } + break; + } + } + imap_append_quoted(dest, src); +} + +static void remove_newlines_and_append(string_t *dest, const char *src) +{ + size_t src_len; + string_t *src_nolf; + src_len = strlen(src); + src_nolf = t_str_new(src_len + 1); + for (size_t i = 0; i < src_len; ++i) { + if (src[i] != '\r' && src[i] != '\n') { + str_append_c(src_nolf, src[i]); + } else if (src[i+1] != ' ' && + src[i+1] != '\t' && + src[i+1] != '\r' && + src[i+1] != '\n' && + src[i+1] != '\0') { + /* ensure whitespace between lines if new line doesn't start with whitespace */ + str_append_c(src_nolf, ' '); + } + } + imap_append_nstring(dest, str_c(src_nolf)); +} + +void imap_append_nstring_nolf(string_t *dest, const char *src) +{ + if (src == NULL || strpbrk(src, "\r\n") == NULL) + imap_append_nstring(dest, src); + else if (buffer_get_pool(dest)->datastack_pool) + remove_newlines_and_append(dest, src); + else T_BEGIN { + remove_newlines_and_append(dest, src); + } T_END; +} + +void imap_append_quoted(string_t *dest, const char *src) +{ + str_append_c(dest, '"'); + for (; *src != '\0'; src++) { + switch (*src) { + case 13: + case 10: + /* not allowed */ + break; + case '"': + case '\\': + str_append_c(dest, '\\'); + str_append_c(dest, *src); + break; + default: + if ((unsigned char)*src >= 0x80) { + /* 8bit input not allowed in dquotes */ + break; + } + + str_append_c(dest, *src); + break; + } + } + str_append_c(dest, '"'); +} + +void imap_append_string_for_humans(string_t *dest, + const unsigned char *src, size_t size) +{ + size_t i, pos, remove_count = 0; + bool whitespace_prefix = TRUE, last_lwsp = TRUE, modify = FALSE; + + /* first check if there is anything to change */ + for (i = 0; i < size; i++) { + switch (src[i]) { + case 0: + /* convert NUL to #0x80 */ + last_lwsp = FALSE; + modify = TRUE; + break; + case 13: + case 10: + case '\t': + modify = TRUE; + /* fall through */ + case ' ': + if (last_lwsp) { + modify = TRUE; + remove_count++; + } + last_lwsp = TRUE; + break; + case '"': + case '\\': + modify = TRUE; + last_lwsp = FALSE; + break; + default: + if ((src[i] & 0x80) != 0) + modify = TRUE; + last_lwsp = FALSE; + break; + } + if (!last_lwsp) + whitespace_prefix = FALSE; + } + if (last_lwsp && i > 0 && !whitespace_prefix) { + modify = TRUE; + remove_count++; + } + if (!modify) { + /* fast path: we can simply write it as quoted string + without any escaping */ + str_append_c(dest, '"'); + str_append_data(dest, src, size); + str_append_c(dest, '"'); + return; + } + if (size == remove_count) { + /* contained only whitespace */ + str_append(dest, "\"\""); + return; + } + + str_printfa(dest, "{%zu}\r\n", size - remove_count); + pos = str_len(dest); + + last_lwsp = TRUE; whitespace_prefix = TRUE; + for (i = 0; i < size; i++) { + switch (src[i]) { + case 0: + str_append_c(dest, 128); + last_lwsp = FALSE; + break; + case 13: + case 10: + case '\t': + case ' ': + if (!last_lwsp) + str_append_c(dest, ' '); + last_lwsp = TRUE; + break; + default: + last_lwsp = FALSE; + str_append_c(dest, src[i]); + break; + } + if (!last_lwsp) + whitespace_prefix = FALSE; + } + if (last_lwsp && i > 0 && !whitespace_prefix) + str_truncate(dest, str_len(dest)-1); + i_assert(str_len(dest) - pos == size - remove_count); +} |