This commit is a large set of code changes and results in removal of
hundreds, perhaps thousands, of CPU instructions, a portion of which
are on hot code paths.
Most (buffer *) used by lighttpd are not NULL, especially since buffers
were inlined into numerous larger structs such as request_st and chunk.
In the small number of instances where that is not the case, a NULL
check is often performed earlier in a function where that buffer is
later used with a buffer_* func. In the handful of cases that remained,
a NULL check was added, e.g. with r->http_host and r->conf.server_tag.
- check for empty strings at config time and set value to NULL if blank
string will be ignored at runtime; at runtime, simple pointer check
for NULL can be used to check for a value that has been set and is not
blank ("")
- use buffer_is_blank() instead of buffer_string_is_empty(),
and use buffer_is_unset() instead of buffer_is_empty(),
where buffer is known not to be NULL so that NULL check can be skipped
- use buffer_clen() instead of buffer_string_length() when buffer is
known not to be NULL (to avoid NULL check at runtime)
- use buffer_truncate() instead of buffer_string_set_length() to
truncate string, and use buffer_extend() to extend
Examples where buffer known not to be NULL:
- cpv->v.b from config_plugin_values_init is not NULL if T_CONFIG_BOOL
(though we might set it to NULL if buffer_is_blank(cpv->v.b))
- address of buffer is arg (&foo)
(compiler optimizer detects this in most, but not all, cases)
- buffer is checked for NULL earlier in func
- buffer is accessed in same scope without a NULL check (e.g. b->ptr)
internal behavior change:
callers must not pass a NULL buffer to some funcs.
- buffer_init_buffer() requires non-null args
- buffer_copy_buffer() requires non-null args
- buffer_append_string_buffer() requires non-null args
- buffer_string_space() requires non-null arg
reuse cache lookup in common case of serving a static file
rather than repeating the stat_cache_entry lookup
(which is more work than memcmp() to re-check stat_cache_entry match)
periodically flush intermediate chunkqueue to r->write_queue
to reduce occurrence of copying to reallocate larger chunk
use chunk_buffer to read ssi file
NB: r->tmp_buf == srv->tmp_buf (pointer is copied for quicker access)
NB: request read and write chunkqueues currently point to connection
chunkqueues; per-request and per-connection chunkqueues are
not distinct from one another
con->read_queue == r->read_queue
con->write_queue == r->write_queue
NB: in the future, a separate connection config may be needed for
connection-level module hooks. Similarly, might need to have
per-request chunkqueues separate from per-connection chunkqueues.
Should probably also have a request_reset() which is distinct from
connection_reset().
e.g. different server.errorlog for different virtual hosts
Also, support different server.breakagelog to have separate script
error logs, applicable to mod_cgi and mod_ssi exec.
convert all log_error_write() to log_error() and pass (log_error_st *)
use con->errh in preference to srv->errh (even though currently same)
avoid passing (server *) when previously used only for logging (errh)
While slightly more memory use in 64-bit (though same memory use as
prior versions of lighttpd), avoids bouncing through second array
when searching in sorted list. Most use of arrays in lighttpd is to
build a list once, and elements are not removed from the list.
This reverts commit 2260a8062ee599ecf28d9b52b981603fd2084aff.
original ordering of array elements is significant
e.g. in lighttpd.conf lists where first match to request is applied
array_get_element_klen() is now intended for read-only access
array_get_data_unset() is used by config processing for r/w access
array_get_buf_ptr() is used for r/w access to ds->value (string buffer)
mark array_get_index() as hot, rewrite to be pure and return sorted pos
mark routines as pure, as appropriate
mark routines as cold if used only at startup for config processing
mark params const, as appropriate
array_get_buf_ptr() for modifiable value buffer after insert into array
uint32_t used and size members instead of size_t
remove a->unique_ndx member; simply add to end of array for value lists
remove du->is_index_key member; simply check buffer_is_empty(du->key)
array_insert_key_value() used to be a hint that lookup could be skipped,
but the state from array_get_index() is now saved and reused internally,
so the distinction is no longer needed. Use array_set_key_value().
