MACROMEDIA DREAMWEAVER 8-EXTENDING DREAMWEAVER, Manual

Page: 458 / 504

458 C-Level Extensibility
The
readContentsOfFile()
function accepts a list of arguments from the user, retrieves the
filename argument, reads the contents of the file, and returns the contents of the file. For
more information about the JavaScript data structures and functions that appear in the
readContentsOfFile()
function, see “C-level extensibility and the JavaScript interpreter”
on page 459 .
JSBool
readContentsOfFile(JSContext *cx, JSObject *obj, unsigned int ¬
argc, jsval *argv, jsval *rval)
{
char *fileName, *fileContents;
JSBool success;
unsigned int length;
/* Make sure caller passed in exactly one argument. If not,
* then tell the interpreter to abort script execution. */
if (argc != 1){
JS_ReportError(cx, "Wrong number of arguments", 0);
return JS_FALSE;
}
/* Convert the argument to a string */
fileName = JS_ValueToString(cx, argv[0], &length);
if (fileName == NULL){
JS_ReportError(cx, "The argument must be a string", 0);
return JS_FALSE;
}
/* Use the string (the file name) to open and read a file */
fileContents = exerciseLeftToTheReader(fileName);
/* Store file contents in rval, which is the return value ¬
passed
* back to the caller */
success = JS_StringToValue(cx, fileContents, 0, *rval);
free(fileContents);
/* Return true to continue or false to abort the script */
return success;
}
To ensure that the
readContentsOfFile()
function executes properly and doesn’t cause a
JavaScript error, you must register the function with the JavaScript interpreter by including a
MM_Init()
function in your library. When Dreamweaver loads the library at startup, it calls
the
MM_Init()
function to get the following three pieces of information:
■
The JavaScript name of the function
■
A pointer to the function
■
The number of arguments that the function expects