1 files changed, 218 insertions, 0 deletions
diff --git a/src/lib-storage/index/dbox-common/dbox-file.h b/src/lib-storage/index/dbox-common/dbox-file.h
new file mode 100644
index 0000000..309c705
--- /dev/null
+++ b/src/lib-storage/index/dbox-common/dbox-file.h
@@ -0,0 +1,218 @@
+#ifndef DBOX_FILE_H
+#define DBOX_FILE_H
+
+/* The file begins with a header followed by zero or more messages:
+
+   <dbox message header>
+   <LF>
+   <message body>
+   <metadata>
+
+   Metadata block begins with DBOX_MAGIC_POST, followed by zero or more lines
+   in format <key character><value><LF>. The block ends with an empty line.
+   Unknown metadata should be ignored, but preserved when copying.
+
+   There should be no duplicates for the current metadata, but future
+   extensions may need them so they should be preserved.
+*/
+#define DBOX_VERSION 2
+#define DBOX_MAGIC_PRE "\001\002"
+#define DBOX_MAGIC_POST "\n\001\003\n"
+
+/* prefer flock(). fcntl() locking currently breaks if trying to access the
+   same file from multiple mail_storages within same process. that's why we
+   fallback to dotlocks. */
+#ifdef HAVE_FLOCK
+#  define DBOX_FILE_LOCK_METHOD_FLOCK
+#endif
+
+struct dbox_file;
+struct stat;
+
+enum dbox_header_key {
+	/* Must be sizeof(struct dbox_message_header) when appending (hex) */
+	DBOX_HEADER_MSG_HEADER_SIZE	= 'M',
+	/* Creation UNIX timestamp (hex) */
+	DBOX_HEADER_CREATE_STAMP	= 'C',
+
+	/* metadata used by old Dovecot versions */
+	DBOX_HEADER_OLDV1_APPEND_OFFSET	= 'A'
+};
+
+/* NOTE: all valid keys are uppercase characters. if this changes, change
+   dbox-file-fix.c:dbox_file_match_post_magic() to recognize them */
+enum dbox_metadata_key {
+	/* Globally unique identifier for the message. Preserved when
+	   copying. */
+	DBOX_METADATA_GUID		= 'G',
+	/* POP3 UIDL overriding the default format */
+	DBOX_METADATA_POP3_UIDL		= 'P',
+	/* POP3 message ordering (for migrated mails) */
+	DBOX_METADATA_POP3_ORDER	= 'O',
+	/* Received UNIX timestamp in hex */
+	DBOX_METADATA_RECEIVED_TIME	= 'R',
+	/* Physical message size in hex. Necessary only if it differs from
+	   the dbox_message_header.message_size_hex, for example because the
+	   message is compressed. */
+	DBOX_METADATA_PHYSICAL_SIZE	= 'Z',
+	/* Virtual message size in hex (line feeds counted as CRLF) */
+	DBOX_METADATA_VIRTUAL_SIZE	= 'V',
+	/* Pointer to external message data. Format is:
+	   1*(<start offset> <byte count> <options> <ref>) */
+	DBOX_METADATA_EXT_REF		= 'X',
+	/* Mailbox name where this message was originally saved to.
+	   When rebuild finds a message whose mailbox is unknown, it's
+	   placed to this mailbox. */
+	DBOX_METADATA_ORIG_MAILBOX	= 'B',
+
+	/* metadata used by old Dovecot versions */
+	DBOX_METADATA_OLDV1_EXPUNGED	= 'E',
+	DBOX_METADATA_OLDV1_FLAGS	= 'F',
+	DBOX_METADATA_OLDV1_KEYWORDS	= 'K',
+	DBOX_METADATA_OLDV1_SAVE_TIME	= 'S',
+	DBOX_METADATA_OLDV1_SPACE	= ' '
+};
+
+enum dbox_message_type {
+	/* Normal message */
+	DBOX_MESSAGE_TYPE_NORMAL	= 'N'
+};
+
+struct dbox_message_header {
+	unsigned char magic_pre[2];
+	unsigned char type;
+	unsigned char space1;
+	unsigned char oldv1_uid_hex[8];
+	unsigned char space2;
+	unsigned char message_size_hex[16];
+	/* <space reserved for future extensions, LF is always last> */
+	unsigned char save_lf;
+};
+
+struct dbox_metadata_header {
+	unsigned char magic_post[sizeof(DBOX_MAGIC_POST)-1];
+};
+
+struct dbox_file {
+	struct dbox_storage *storage;
+	int refcount;
+
+	time_t create_time;
+	unsigned int file_version;
+	unsigned int file_header_size;
+	unsigned int msg_header_size;
+
+	const char *cur_path;
+	char *primary_path, *alt_path;
+	int fd;
+	struct istream *input;
+#ifdef DBOX_FILE_LOCK_METHOD_FLOCK
+	struct file_lock *lock;
+#else
+	struct dotlock *lock;
+#endif
+
+	uoff_t cur_offset;
+	uoff_t cur_physical_size;
+
+	/* Metadata for the currently seeked metadata block. */
+	pool_t metadata_pool;
+	ARRAY(const char *) metadata;
+	uoff_t metadata_read_offset;
+
+	bool appending:1;
+	bool corrupted:1;
+};
+
+struct dbox_file_append_context {
+	struct dbox_file *file;
+
+	uoff_t first_append_offset, last_checkpoint_offset, last_flush_offset;
+	struct ostream *output;
+};
+
+#define dbox_file_is_open(file) ((file)->fd != -1)
+#define dbox_file_is_in_alt(file) ((file)->cur_path == (file)->alt_path)
+
+void dbox_file_init(struct dbox_file *file);
+void dbox_file_unref(struct dbox_file **file);
+
+/* Open the file. Returns 1 if ok, 0 if file header is corrupted, -1 if error.
+   If file is deleted, deleted_r=TRUE and 1 is returned. */
+int dbox_file_open(struct dbox_file *file, bool *deleted_r);
+/* Try to open file only from primary path. */
+int dbox_file_open_primary(struct dbox_file *file, bool *notfound_r);
+/* Close the file handle from the file, but don't free it. */
+void dbox_file_close(struct dbox_file *file);
+
+/* fstat() or stat() the file. If file is already deleted, fails with
+   errno=ENOENT. */
+int dbox_file_stat(struct dbox_file *file, struct stat *st_r);
+
+/* Try to lock the dbox file. Returns 1 if ok, 0 if already locked by someone
+   else, -1 if error. */
+int dbox_file_try_lock(struct dbox_file *file);
+void dbox_file_unlock(struct dbox_file *file);
+
+/* Seek to given offset in file. Returns 1 if ok/expunged, 0 if file/offset is
+   corrupted, -1 if I/O error. */
+int dbox_file_seek(struct dbox_file *file, uoff_t offset);
+/* Start seeking at the beginning of the file. */
+void dbox_file_seek_rewind(struct dbox_file *file);
+/* Seek to next message after current one. If there are no more messages,
+   returns 0 and last_r is set to TRUE. Returns 1 if ok, 0 if file is
+   corrupted, -1 if I/O error. */
+int dbox_file_seek_next(struct dbox_file *file, uoff_t *offset_r, bool *last_r);
+
+/* Start appending to dbox file */
+struct dbox_file_append_context *dbox_file_append_init(struct dbox_file *file);
+/* Finish writing appended mails. */
+int dbox_file_append_commit(struct dbox_file_append_context **ctx);
+/* Truncate appended mails. */
+void dbox_file_append_rollback(struct dbox_file_append_context **ctx);
+/* Get output stream for appending a new message. Returns 1 if ok, 0 if file
+   can't be appended to (old file version or corruption) or -1 if error. */
+int dbox_file_get_append_stream(struct dbox_file_append_context *ctx,
+				struct ostream **output_r);
+/* Call after message has been fully saved. If this isn't done, the writes
+   since the last checkpoint are truncated. */
+void dbox_file_append_checkpoint(struct dbox_file_append_context *ctx);
+/* Flush output buffer. */
+int dbox_file_append_flush(struct dbox_file_append_context *ctx);
+
+/* Read current message's metadata. Returns 1 if ok, 0 if metadata is
+   corrupted, -1 if I/O error. */
+int dbox_file_metadata_read(struct dbox_file *file);
+/* Return wanted metadata value, or NULL if not found. */
+const char *dbox_file_metadata_get(struct dbox_file *file,
+				   enum dbox_metadata_key key);
+
+/* Returns DBOX_METADATA_PHYSICAL_SIZE if set, otherwise physical size from
+   header. They differ only for e.g. compressed mails. */
+uoff_t dbox_file_get_plaintext_size(struct dbox_file *file);
+
+/* Fix a broken dbox file by rename()ing over it with a fixed file. Everything
+   before start_offset is assumed to be valid and is simply copied. The file
+   is reopened afterwards. Returns 1 if ok, 0 if the resulting file has no
+   mails and was deleted, -1 if I/O error. */
+int dbox_file_fix(struct dbox_file *file, uoff_t start_offset);
+/* Delete the given dbox file. Returns 1 if deleted, 0 if file wasn't found
+   or -1 if error. */
+int dbox_file_unlink(struct dbox_file *file);
+
+/* Fill dbox_message_header with given size. */
+void dbox_msg_header_fill(struct dbox_message_header *dbox_msg_hdr,
+			  uoff_t message_size);
+
+void dbox_file_set_syscall_error(struct dbox_file *file, const char *function);
+void dbox_file_set_corrupted(struct dbox_file *file, const char *reason, ...)
+	ATTR_FORMAT(2, 3);
+
+/* private: */
+const char *dbox_generate_tmp_filename(void);
+void dbox_file_free(struct dbox_file *file);
+int dbox_file_header_write(struct dbox_file *file, struct ostream *output);
+int dbox_file_read_mail_header(struct dbox_file *file, uoff_t *physical_size_r);
+int dbox_file_metadata_skip_header(struct dbox_file *file);
+
+#endif