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Tweak the API to be more consistent.
Update docs.
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@@ -4,9 +4,6 @@ $Id$ | |
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Please send comments to: Wez Furlong <[email protected]> | ||
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Note: this doc is preliminary and is intended to give the reader an idea of | ||
how streams work and should be used. | ||
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Why Streams? | ||
============ | ||
You may have noticed a shed-load of issock parameters flying around the PHP | ||
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@@ -26,7 +23,7 @@ The main functions are: | |
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PHPAPI size_t php_stream_read(php_stream * stream, char * buf, size_t count); | ||
PHPAPI size_t php_stream_write(php_stream * stream, const char * buf, size_t | ||
count); | ||
count); | ||
PHPAPI int php_stream_eof(php_stream * stream); | ||
PHPAPI int php_stream_getc(php_stream * stream); | ||
PHPAPI char *php_stream_gets(php_stream * stream, char *buf, size_t maxlen); | ||
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@@ -40,16 +37,77 @@ names: fread, fwrite, feof, fgetc, fgets, fclose, fflush, fseek, ftell. | |
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Opening Streams | ||
=============== | ||
Ultimately, I aim to implement an fopen_wrapper-like call to do this with | ||
minimum fuss. | ||
Currently, mostly for testing purposes, you can use php_stream_fopen to open a | ||
stream on a regular file. | ||
In most cases, you should use this API: | ||
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PHPAPI php_stream *php_stream_open_wrapper(char *path, char *mode, | ||
int options, char **opened_path TSRMLS_DC); | ||
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Where: | ||
path is the file or resource to open. | ||
mode is the stdio compatible mode eg: "wb", "rb" etc. | ||
options is a combination of the following values: | ||
IGNORE_PATH (default) - don't use include path to search for the file | ||
USE_PATH - use include path to search for the file | ||
IGNORE_URL - do not use plugin wrappers | ||
REPORT_ERRORS - show errors in a standard format if something | ||
goes wrong. | ||
opened_path is used to return the path of the actual file opened. | ||
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If you need to open a specific stream, or convert standard resources into | ||
streams there are a range of functions to do this defined in php_streams.h. | ||
A brief list of the most commonly used functions: | ||
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PHPAPI php_stream *php_stream_fopen_from_file(FILE *file, const char *mode); | ||
Convert a FILE * into a stream. | ||
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PHPAPI php_stream * php_stream_fopen(const char * filename, const char * | ||
mode); | ||
PHPAPI php_stream *php_stream_fopen_tmpfile(void); | ||
Open a FILE * with tmpfile() and convert into a stream. | ||
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This call behaves just like fopen(), except it returns a stream instead of a | ||
FILE * | ||
PHPAPI php_stream *php_stream_fopen_temporary_file(const char *dir, | ||
const char *pfx, char **opened_path TSRMLS_DC); | ||
Generate a temporary file name and open it. | ||
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There are some network enabled relatives in php_network.h: | ||
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PHPAPI php_stream *php_stream_sock_open_from_socket(int socket, int persistent); | ||
Convert a socket into a stream. | ||
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PHPAPI php_stream *php_stream_sock_open_host(const char *host, unsigned short port, | ||
int socktype, int timeout, int persistent); | ||
Open a connection to a host and return a stream. | ||
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PHPAPI php_stream *php_stream_sock_open_unix(const char *path, int persistent, | ||
struct timeval *timeout); | ||
Open a UNIX domain socket. | ||
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Stream Utilities | ||
================ | ||
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If you need to copy some data from one stream to another, you will be please | ||
to know that the streams API provides a standard way to do this: | ||
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PHPAPI size_t php_stream_copy_to_stream(php_stream *src, | ||
php_stream *dest, size_t maxlen); | ||
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If you want to copy all remaining data from the src stream, pass | ||
PHP_STREAM_COPY_ALL as the maxlen parameter, otherwise maxlen indicates the | ||
number of bytes to copy. | ||
This function will try to use mmap where available to make the copying more | ||
efficient. | ||
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If you want to read the contents of a stream into an allocated memory buffer, | ||
you should use: | ||
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PHPAPI size_t php_stream_copy_to_mem(php_stream *src, char **buf, | ||
size_t maxlen, int persistent); | ||
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This function will set buf to the address of the buffer that it allocated, | ||
which will be maxlen bytes in length, or will be the entire length of the | ||
data remaining on the stream if you set maxlen to PHP_STREAM_COPY_ALL. | ||
The buffer is allocated using pemalloc(); you need to call pefree() to | ||
release the memory when you are done. | ||
As with copy_to_stream, this function will try use mmap where it can. | ||
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Casting Streams | ||
=============== | ||
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@@ -59,14 +117,14 @@ You need to "cast" the stream into a FILE*, and this is how you do it: | |
FILE * fp; | ||
php_stream * stream; /* already opened */ | ||
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if (php_stream_cast(stream, PHP_STREAM_AS_STDIO, &fp, 1) == FAILURE) { | ||
RETURN_FALSE; | ||
if (php_stream_cast(stream, PHP_STREAM_AS_STDIO, (void*)&fp, REPORT_ERRORS) == FAILURE) { | ||
RETURN_FALSE; | ||
} | ||
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The prototype is: | ||
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PHPAPI int php_stream_cast(php_stream * stream, int castas, void ** ret, int | ||
show_err); | ||
show_err); | ||
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The show_err parameter, if non-zero, will cause the function to display an | ||
appropriate error message of type E_WARNING if the cast fails. | ||
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@@ -83,8 +141,14 @@ if you mix ANSI stdio calls on the FILE* with php stream calls on the stream. | |
If your system has the fopencookie function, php streams can synthesize a | ||
FILE* on top of any stream, which is useful for SSL sockets, memory based | ||
streams, data base streams etc. etc. | ||
NOTE: There might be situations where this is not desireable, and we need to | ||
provide a flag to inform the casting routine of this. | ||
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In situations where this is not desireable, you should query the stream | ||
to see if it naturally supports FILE *. You can use this code snippet | ||
for this purpose: | ||
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if (php_stream_is(stream, PHP_STREAM_IS_STDIO)) { | ||
/* can safely cast to FILE* with no adverse side effects */ | ||
} | ||
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You can use: | ||
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@@ -93,10 +157,15 @@ PHPAPI int php_stream_can_cast(php_stream * stream, int castas) | |
to find out if a stream can be cast, without actually performing the cast, so | ||
to check if a stream is a socket you might use: | ||
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if (php_stream_can_cast(stream, PHP_STREAM_AS_SOCKETD) == SUCCESS) { | ||
/* it's a socket */ | ||
if (php_stream_can_cast(stream, PHP_STREAM_AS_SOCKETD) == SUCCESS) { | ||
/* it can be a socket */ | ||
} | ||
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Please note the difference between php_stream_is and php_stream_can_cast; | ||
stream_is tells you if the stream is a particular type of stream, whereas | ||
can_cast tells you if the stream can be forced into the form you request. | ||
The format doesn't change anything, while the later *might* change some | ||
state in the stream. | ||
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Stream Internals | ||
================ | ||
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@@ -121,17 +190,17 @@ As an example, the php_stream_fopen() function looks like this: | |
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PHPAPI php_stream * php_stream_fopen(const char * filename, const char * mode) | ||
{ | ||
FILE * fp = fopen(filename, mode); | ||
php_stream * ret; | ||
if (fp) { | ||
ret = php_stream_alloc(&php_stream_stdio_ops, fp, 0, 0, mode); | ||
if (ret) | ||
return ret; | ||
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fclose(fp); | ||
} | ||
return NULL; | ||
FILE * fp = fopen(filename, mode); | ||
php_stream * ret; | ||
if (fp) { | ||
ret = php_stream_alloc(&php_stream_stdio_ops, fp, 0, 0, mode); | ||
if (ret) | ||
return ret; | ||
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fclose(fp); | ||
} | ||
return NULL; | ||
} | ||
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php_stream_stdio_ops is a php_stream_ops structure that can be used to handle | ||
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@@ -143,7 +212,7 @@ to be passed back to fopen_wrapper (or it's yet to be implemented successor). | |
The prototype for php_stream_alloc is this: | ||
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PHPAPI php_stream * php_stream_alloc(php_stream_ops * ops, void * abstract, | ||
size_t bufsize, int persistent, const char * mode) | ||
size_t bufsize, int persistent, const char * mode) | ||
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ops is a pointer to the implementation, | ||
abstract holds implementation specific data that is relevant to this instance | ||
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@@ -176,9 +245,9 @@ appropriately), and use the abstract pointer to refer to it. | |
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For structured state you might have this: | ||
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struct my_state { | ||
MYSQL conn; | ||
MYSQL_RES * result; | ||
struct my_state { | ||
MYSQL conn; | ||
MYSQL_RES * result; | ||
}; | ||
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struct my_state * state = pemalloc(sizeof(struct my_state), persistent); | ||
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@@ -201,32 +270,32 @@ For example, for reading from this wierd mysql stream: | |
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static size_t php_mysqlop_read(php_stream * stream, char * buf, size_t count) | ||
{ | ||
struct my_state * state = (struct my_state*)stream->abstract; | ||
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if (buf == NULL && count == 0) { | ||
/* in this special case, php_streams is asking if we have reached the | ||
* end of file */ | ||
if (... at end of file ...) | ||
return EOF; | ||
else | ||
return 0; | ||
} | ||
/* pull out some data from the stream and put it in buf */ | ||
... mysql_fetch_row(state->result) ... | ||
/* we could do something strange, like format the data as XML here, | ||
and place that in the buf, but that brings in some complexities, | ||
such as coping with a buffer size too small to hold the data, | ||
so I won't even go in to how to do that here */ | ||
struct my_state * state = (struct my_state*)stream->abstract; | ||
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if (buf == NULL && count == 0) { | ||
/* in this special case, php_streams is asking if we have reached the | ||
* end of file */ | ||
if (... at end of file ...) | ||
return EOF; | ||
else | ||
return 0; | ||
} | ||
/* pull out some data from the stream and put it in buf */ | ||
... mysql_fetch_row(state->result) ... | ||
/* we could do something strange, like format the data as XML here, | ||
and place that in the buf, but that brings in some complexities, | ||
such as coping with a buffer size too small to hold the data, | ||
so I won't even go in to how to do that here */ | ||
} | ||
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Implement the other operations - remember that write, read, close and flush | ||
are all mandatory. The rest are optional. Declare your stream ops struct: | ||
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php_stream_ops my_ops = { | ||
php_mysqlop_write, php_mysqlop_read, php_mysqlop_close, | ||
php_mysqlop_flush, NULL, NULL, NULL, | ||
"Strange mySQL example" | ||
php_mysqlop_write, php_mysqlop_read, php_mysqlop_close, | ||
php_mysqlop_flush, NULL, NULL, NULL, | ||
"Strange mySQL example" | ||
} | ||
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Thats it! | ||
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@@ -240,4 +309,4 @@ connection and then use pefree to dispose of the struct you allocated. | |
You may read the stream->persistent field to determine if your struct was | ||
allocated in persistent mode or not. | ||
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vim:tw=78 | ||
vim:tw=78:et |
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