In the zipfs archive initialization, use Tcl_SetPreInitScript() to equip

the creation of every interp by the Tcl library with the knowledge of where
in the archive the script library is to be found.

This is the **documented example usage** for Tcl_SetPreInitScript.

POSTSCRIPT: Moved to development branch.  Still needs some verification.

1 files changed, 45 insertions, 13 deletions

diff --git a/generic/tclZipfs.c b/generic/tclZipfs.c
index 842d51a..4d95973 100644
--- a/generic/tclZipfs.c
+++ b/generic/tclZipfs.c
@@ -91,6 +91,17 @@ static const z_crc_t* crc32tab;
 #define ZIPFS_VOLUME_LEN  9
 #define ZIPFS_APP_MOUNT	  ZIPFS_VOLUME "app"
 #define ZIPFS_ZIP_MOUNT	  ZIPFS_VOLUME "lib/tcl"
+
+#define ZIPFS_SCRIPT_PREFIX	"set ::tcl_library "
+#define ZIPFS_TCL_LIBRARY_1	ZIPFS_APP_MOUNT "/tcl_library"
+#define ZIPFS_INIT_SCRIPT_1	ZIPFS_SCRIPT_PREFIX ZIPFS_TCL_LIBRARY_1
+
+#define ZIPFS_TCL_LIBRARY_2	ZIPFS_ZIP_MOUNT
+#define ZIPFS_INIT_SCRIPT_2	ZIPFS_SCRIPT_PREFIX ZIPFS_TCL_LIBRARY_2
+
+#define ZIPFS_TCL_LIBRARY_3	ZIPFS_ZIP_MOUNT "/tcl_library"
+#define ZIPFS_INIT_SCRIPT_3	ZIPFS_SCRIPT_PREFIX ZIPFS_TCL_LIBRARY_3
+
 #define ZIPFS_FALLBACK_ENCODING "cp437"
 
 /*
@@ -313,6 +324,7 @@ static const char pwrot[17] =
     "\x10\x90\x50\xD0\x30\xB0\x70\xF0";
 
 static const char *zipfs_literal_tcl_library = NULL;
+static const char *zipfs_init_script = NULL;
 
 /* Function prototypes */
 
@@ -4231,6 +4243,28 @@ ScriptLibrarySetup(
     Tcl_Obj *libDirObj = Tcl_NewStringObj(dirName, -1);
     Tcl_Obj *subDirObj, *searchPathObj;
 
+    /*
+     * We know where the init.tcl is located in the attached script library
+     * archive.  Use a pre-init script to tell every Tcl interp as it gets
+     * created where that is, so none of them need to construct and then
+     * iterate through some search path.  That's the literal documented
+     * purpose of Tcl_SetPreInitScript().  Use it.
+     *
+     * TODO: Examine why we need so many variations and eliminate as many
+     * as possible.
+     */
+
+    if (0 == strcmp(zipfs_literal_tcl_library, ZIPFS_TCL_LIBRARY_1)) {
+	zipfs_init_script = ZIPFS_INIT_SCRIPT_1;
+    } else if (0 == strcmp(zipfs_literal_tcl_library, ZIPFS_TCL_LIBRARY_2)) {
+	zipfs_init_script = ZIPFS_INIT_SCRIPT_2;
+    } else if (0 == strcmp(zipfs_literal_tcl_library, ZIPFS_TCL_LIBRARY_3)) {
+	zipfs_init_script = ZIPFS_INIT_SCRIPT_3;
+    }
+    if (zipfs_init_script) {
+	Tcl_SetPreInitScript(zipfs_init_script);
+    }
+
     TclNewLiteralStringObj(subDirObj, "encoding");
     Tcl_IncrRefCount(subDirObj);
     TclNewObj(searchPathObj);
@@ -4268,13 +4302,12 @@ TclZipfs_TclLibrary(void)
      * Look for the library file system within the executable.
      */
 
-    vfsInitScript = Tcl_NewStringObj(ZIPFS_APP_MOUNT "/tcl_library/init.tcl",
-	    -1);
+    vfsInitScript = Tcl_NewStringObj(ZIPFS_TCL_LIBRARY_1 "/init.tcl", -1);
     Tcl_IncrRefCount(vfsInitScript);
     found = Tcl_FSAccess(vfsInitScript, F_OK);
     Tcl_DecrRefCount(vfsInitScript);
     if (found == TCL_OK) {
-	zipfs_literal_tcl_library = ZIPFS_APP_MOUNT "/tcl_library";
+	zipfs_literal_tcl_library = ZIPFS_TCL_LIBRARY_1;
 	return ScriptLibrarySetup(zipfs_literal_tcl_library);
     }
 
@@ -6283,22 +6316,21 @@ ZipfsAppHookFindTclInit(
 	return TCL_ERROR;
     }
 
-    TclNewLiteralStringObj(vfsInitScript, ZIPFS_ZIP_MOUNT "/init.tcl");
+    TclNewLiteralStringObj(vfsInitScript, ZIPFS_TCL_LIBRARY_2 "/init.tcl");
     Tcl_IncrRefCount(vfsInitScript);
     found = Tcl_FSAccess(vfsInitScript, F_OK);
     Tcl_DecrRefCount(vfsInitScript);
     if (found == 0) {
-	zipfs_literal_tcl_library = ZIPFS_ZIP_MOUNT;
+	zipfs_literal_tcl_library = ZIPFS_TCL_LIBRARY_2;
 	return TCL_OK;
     }
 
-    TclNewLiteralStringObj(vfsInitScript,
-	    ZIPFS_ZIP_MOUNT "/tcl_library/init.tcl");
+    TclNewLiteralStringObj(vfsInitScript, ZIPFS_TCL_LIBRARY_3 "/init.tcl");
     Tcl_IncrRefCount(vfsInitScript);
     found = Tcl_FSAccess(vfsInitScript, F_OK);
     Tcl_DecrRefCount(vfsInitScript);
     if (found == 0) {
-	zipfs_literal_tcl_library = ZIPFS_ZIP_MOUNT "/tcl_library";
+	zipfs_literal_tcl_library = ZIPFS_TCL_LIBRARY_3;
 	return TCL_OK;
     }
 
@@ -6415,12 +6447,12 @@ TclZipfs_AppHook(
 
 	if (!zipfs_literal_tcl_library) {
 	    TclNewLiteralStringObj(vfsInitScript,
-		    ZIPFS_APP_MOUNT "/tcl_library/init.tcl");
+		    ZIPFS_TCL_LIBRARY_1 "/init.tcl");
 	    Tcl_IncrRefCount(vfsInitScript);
 	    found = Tcl_FSAccess(vfsInitScript, F_OK);
 	    Tcl_DecrRefCount(vfsInitScript);
 	    if (found == TCL_OK) {
-		zipfs_literal_tcl_library = ZIPFS_APP_MOUNT "/tcl_library";
+		zipfs_literal_tcl_library = ZIPFS_TCL_LIBRARY_1;
 		return version;
 	    }
 	}
@@ -6449,7 +6481,7 @@ TclZipfs_AppHook(
 
 	    TclZipfs_TclLibrary();
 	    TclNewLiteralStringObj(vfsInitScript,
-		    ZIPFS_ZIP_MOUNT "/tcl_library/install.tcl");
+		    ZIPFS_TCL_LIBRARY_3 "install.tcl");
 	    Tcl_IncrRefCount(vfsInitScript);
 	    if (Tcl_FSAccess(vfsInitScript, F_OK) == 0) {
 		Tcl_SetStartupScript(vfsInitScript, NULL);
@@ -6472,12 +6504,12 @@ TclZipfs_AppHook(
 	    }
 	    /* Set Tcl Encodings */
 	    TclNewLiteralStringObj(vfsInitScript,
-		    ZIPFS_APP_MOUNT "/tcl_library/init.tcl");
+		    ZIPFS_TCL_LIBRARY_1 "/init.tcl");
 	    Tcl_IncrRefCount(vfsInitScript);
 	    found = Tcl_FSAccess(vfsInitScript, F_OK);
 	    Tcl_DecrRefCount(vfsInitScript);
 	    if (found == TCL_OK) {
-		zipfs_literal_tcl_library = ZIPFS_APP_MOUNT "/tcl_library";
+		zipfs_literal_tcl_library = ZIPFS_TCL_LIBRARY_1;
 		return version;
 	    }
 	}