tclpkg.c

linux系统下的音频通信

/* 
 * tclPkg.c --
 *
 *	This file implements package and version control for Tcl via
 *	the "package" command and a few C APIs.
 *
 * Copyright (c) 1996 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS: @(#) tclPkg.c 1.9 97/05/14 13:23:51
 */

#include "tclInt.h"

/*
 * Each invocation of the "package ifneeded" command creates a structure
 * of the following type, which is used to load the package into the
 * interpreter if it is requested with a "package require" command.
 */

typedef struct PkgAvail {
    char *version;		/* Version string; malloc'ed. */
    char *script;		/* Script to invoke to provide this version
				 * of the package.  Malloc'ed and protected
				 * by Tcl_Preserve and Tcl_Release. */
    struct PkgAvail *nextPtr;	/* Next in list of available versions of
				 * the same package. */
} PkgAvail;

/*
 * For each package that is known in any way to an interpreter, there
 * is one record of the following type.  These records are stored in
 * the "packageTable" hash table in the interpreter, keyed by
 * package name such as "Tk" (no version number).
 */

typedef struct Package {
    char *version;		/* Version that has been supplied in this
				 * interpreter via "package provide"
				 * (malloc'ed).  NULL means the package doesn't
				 * exist in this interpreter yet. */
    PkgAvail *availPtr;		/* First in list of all available versions
				 * of this package. */
} Package;

/*
 * Prototypes for procedures defined in this file:
 */

static int		CheckVersion _ANSI_ARGS_((Tcl_Interp *interp,
			    char *string));
static int		ComparePkgVersions _ANSI_ARGS_((char *v1, char *v2,
			    int *satPtr));
static Package *	FindPackage _ANSI_ARGS_((Tcl_Interp *interp,
			    char *name));

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PkgProvide --
 *
 *	This procedure is invoked to declare that a particular version
 *	of a particular package is now present in an interpreter.  There
 *	must not be any other version of this package already
 *	provided in the interpreter.
 *
 * Results:
 *	Normally returns TCL_OK;  if there is already another version
 *	of the package loaded then TCL_ERROR is returned and an error
 *	message is left in interp->result.
 *
 * Side effects:
 *	The interpreter remembers that this package is available,
 *	so that no other version of the package may be provided for
 *	the interpreter.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_PkgProvide(interp, name, version)
    Tcl_Interp *interp;		/* Interpreter in which package is now
				 * available. */
    char *name;			/* Name of package. */
    char *version;		/* Version string for package. */
{
    Package *pkgPtr;

    pkgPtr = FindPackage(interp, name);
    if (pkgPtr->version == NULL) {
	pkgPtr->version = ckalloc((unsigned) (strlen(version) + 1));
	strcpy(pkgPtr->version, version);
	return TCL_OK;
    }
    if (ComparePkgVersions(pkgPtr->version, version, (int *) NULL) == 0) {
	return TCL_OK;
    }
    Tcl_AppendResult(interp, "conflicting versions provided for package \"",
	    name, "\": ", pkgPtr->version, ", then ", version, (char *) NULL);
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PkgRequire --
 *
 *	This procedure is called by code that depends on a particular
 *	version of a particular package.  If the package is not already
 *	provided in the interpreter, this procedure invokes a Tcl script
 *	to provide it.  If the package is already provided, this
 *	procedure makes sure that the caller's needs don't conflict with
 *	the version that is present.
 *
 * Results:
 *	If successful, returns the version string for the currently
 *	provided version of the package, which may be different from
 *	the "version" argument.  If the caller's requirements
 *	cannot be met (e.g. the version requested conflicts with
 *	a currently provided version, or the required version cannot
 *	be found, or the script to provide the required version
 *	generates an error), NULL is returned and an error
 *	message is left in interp->result.
 *
 * Side effects:
 *	The script from some previous "package ifneeded" command may
 *	be invoked to provide the package.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_PkgRequire(interp, name, version, exact)
    Tcl_Interp *interp;		/* Interpreter in which package is now
				 * available. */
    char *name;			/* Name of desired package. */
    char *version;		/* Version string for desired version;
				 * NULL means use the latest version
				 * available. */
    int exact;			/* Non-zero means that only the particular
				 * version given is acceptable. Zero means
				 * use the latest compatible version. */
{
    Package *pkgPtr;
    PkgAvail *availPtr, *bestPtr;
    char *script;
    int code, satisfies, result, pass;
    Tcl_DString command;

    /*
     * It can take up to three passes to find the package:  one pass to
     * run the "package unknown" script, one to run the "package ifneeded"
     * script for a specific version, and a final pass to lookup the
     * package loaded by the "package ifneeded" script.
     */

    for (pass = 1; ; pass++) {
	pkgPtr = FindPackage(interp, name);
	if (pkgPtr->version != NULL) {
	    break;
	}

	/*
	 * The package isn't yet present.  Search the list of available
	 * versions and invoke the script for the best available version.
	 */
    
	bestPtr = NULL;
	for (availPtr = pkgPtr->availPtr; availPtr != NULL;
		availPtr = availPtr->nextPtr) {
	    if ((bestPtr != NULL) && (ComparePkgVersions(availPtr->version,
		    bestPtr->version, (int *) NULL) <= 0)) {
		continue;
	    }
	    if (version != NULL) {
		result = ComparePkgVersions(availPtr->version, version,
			&satisfies);
		if ((result != 0) && exact) {
		    continue;
		}
		if (!satisfies) {
		    continue;
		}
	    }
	    bestPtr = availPtr;
	}
	if (bestPtr != NULL) {
	    /*
	     * We found an ifneeded script for the package.  Be careful while
	     * executing it:  this could cause reentrancy, so (a) protect the
	     * script itself from deletion and (b) don't assume that bestPtr
	     * will still exist when the script completes.
	     */
	
	    script = bestPtr->script;
	    Tcl_Preserve((ClientData) script);
	    code = Tcl_GlobalEval(interp, script);
	    Tcl_Release((ClientData) script);
	    if (code != TCL_OK) {
		if (code == TCL_ERROR) {
		    Tcl_AddErrorInfo(interp,
			    "\n    (\"package ifneeded\" script)");
		}
		return NULL;
	    }
	    Tcl_ResetResult(interp);
	    pkgPtr = FindPackage(interp, name);
	    break;
	}

	/*
	 * Package not in the database.  If there is a "package unknown"
	 * command, invoke it (but only on the first pass;  after that,
	 * we should not get here in the first place).
	 */

	if (pass > 1) {
	    break;
	}
	script = ((Interp *) interp)->packageUnknown;
	if (script != NULL) {
	    Tcl_DStringInit(&command);
	    Tcl_DStringAppend(&command, script, -1);
	    Tcl_DStringAppendElement(&command, name);
	    Tcl_DStringAppend(&command, " ", 1);
	    Tcl_DStringAppend(&command, (version != NULL) ? version : "{}",
		    -1);
	    if (exact) {
		Tcl_DStringAppend(&command, " -exact", 7);
	    }
	    code = Tcl_GlobalEval(interp, Tcl_DStringValue(&command));
	    Tcl_DStringFree(&command);
	    if (code != TCL_OK) {
		if (code == TCL_ERROR) {
		    Tcl_AddErrorInfo(interp,
			    "\n    (\"package unknown\" script)");
		}
		return NULL;
	    }
	    Tcl_ResetResult(interp);
	}
    }

    if (pkgPtr->version == NULL) {
	Tcl_AppendResult(interp, "can't find package ", name,
		(char *) NULL);
	if (version != NULL) {
	    Tcl_AppendResult(interp, " ", version, (char *) NULL);
	}
	return NULL;
    }

    /*
     * At this point we now that the package is present.  Make sure that the
     * provided version meets the current requirement.
     */

    if (version == NULL) {
	return pkgPtr->version;
    }
    result = ComparePkgVersions(pkgPtr->version, version, &satisfies);
    if ((satisfies && !exact) || (result == 0)) {
	return pkgPtr->version;
    }
    Tcl_AppendResult(interp, "version conflict for package \"",
	    name, "\": have ", pkgPtr->version, ", need ", version,
	    (char *) NULL);
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PackageCmd --
 *
 *	This procedure is invoked to process the "package" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
Tcl_PackageCmd(dummy, interp, argc, argv)
    ClientData dummy;			/* Not used. */
    Tcl_Interp *interp;			/* Current interpreter. */
    int argc;				/* Number of arguments. */
    char **argv;			/* Argument strings. */
{
    Interp *iPtr = (Interp *) interp;
    size_t length;
    int c, exact, i, satisfies;
    PkgAvail *availPtr, *prevPtr;
    Package *pkgPtr;
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch search;
    Tcl_HashTable *tablePtr;
    char *version;
    char buf[30];

    if (argc < 2) {
	Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		" option ?arg arg ...?\"", (char *) NULL);
	return TCL_ERROR;
    }
    c = argv[1][0];
    length = strlen(argv[1]);
    if ((c == 'f') && (strncmp(argv[1], "forget", length) == 0)) {
	for (i = 2; i < argc; i++) {
	    hPtr = Tcl_FindHashEntry(&iPtr->packageTable, argv[i]);
	    if (hPtr == NULL) {
		return TCL_OK;
	    }
	    pkgPtr = (Package *) Tcl_GetHashValue(hPtr);
	    Tcl_DeleteHashEntry(hPtr);
	    if (pkgPtr->version != NULL) {
		ckfree(pkgPtr->version);
	    }
	    while (pkgPtr->availPtr != NULL) {
		availPtr = pkgPtr->availPtr;
		pkgPtr->availPtr = availPtr->nextPtr;
		ckfree(availPtr->version);
		Tcl_EventuallyFree((ClientData)availPtr->script, TCL_DYNAMIC);
		ckfree((char *) availPtr);
	    }
	    ckfree((char *) pkgPtr);
	}
    } else if ((c == 'i') && (strncmp(argv[1], "ifneeded", length) == 0)) {
	if ((argc != 4) && (argc != 5)) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " ifneeded package version ?script?\"", (char *) NULL);
	    return TCL_ERROR;
	}
	if (CheckVersion(interp, argv[3]) != TCL_OK) {
	    return TCL_ERROR;
	}
	if (argc == 4) {
	    hPtr = Tcl_FindHashEntry(&iPtr->packageTable, argv[2]);
	    if (hPtr == NULL) {
		return TCL_OK;
	    }
	    pkgPtr = (Package *) Tcl_GetHashValue(hPtr);
	} else {
	    pkgPtr = FindPackage(interp, argv[2]);
	}
	for (availPtr = pkgPtr->availPtr, prevPtr = NULL; availPtr != NULL;
		prevPtr = availPtr, availPtr = availPtr->nextPtr) {
	    if (ComparePkgVersions(availPtr->version, argv[3], (int *) NULL)
		    == 0) {
		if (argc == 4) {
		    Tcl_SetResult(interp, availPtr->script, TCL_VOLATILE);
		    return TCL_OK;
		}
		Tcl_EventuallyFree((ClientData)availPtr->script, TCL_DYNAMIC);
		break;
	    }
	}
	if (argc == 4) {
	    return TCL_OK;
	}