Give meaningful error messages.

Makefile

@@ -11,7 +11,7 @@ NETDISKINIT_OBJS = initstart.a netdiskinit.a hostname.a http.a readtcp.a seturl.
 # NETDISKINIT_RSRC = 
 NETDISKINIT_PROG = NetDiskInit
 
-NETDISKCDEV_OBJS = cdev.a cdevutil.a
+NETDISKCDEV_OBJS = cdev.a cdevutil.a netdiskerror.a
 NETDISKCDEV_RSRC = cdev.rez
 NETDISKCDEV_CDEV = NetDisk
 

cdev.c

@@ -48,6 +48,7 @@ void DoMount(void)
 {
     char numStr[6] = "";
     char *subs[1] = {numStr};
+    static char alertString[200];
 
     WaitCursor();
 
@@ -64,10 +65,11 @@ void DoMount(void)
     InitCursor();
 
     if (mountURLRec.result != OPERATION_SUCCESSFUL) {
-        //TODO better error messages
         snprintf(numStr, sizeof(numStr), "%u", mountURLRec.result);
-        AlertWindow(awResource+awCString+awButtonLayout, (Pointer)subs,
-                    mountURLError);
+        snprintf(alertString, sizeof(alertString), "42~%.175s~^#0\0",
+                 ErrorString(mountURLRec.result));
+        AlertWindow(awPointer+awCString+awButtonLayout, (Pointer)subs,
+                    (Ref)alertString);
         
         /* Work around issue where parts of LE caret may flash out of sync */
         CtlRecHndl ctl = GetCtlHandleFromID(wPtr, urlLine);

driver.c

@@ -1,3 +1,5 @@
+#pragma noroot
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <gsos.h>

http.c

@@ -218,7 +218,12 @@ netRetry:
             result = EXCESSIVE_REDIRECTS;
             goto errorReturn;
         }
-              
+
+    /* Full content in response to range request: not supported by NetDisk */
+    case 200:
+        result = NOT_DESIRED_CONTENT;
+        goto errorReturn;
+      
     default:
         if (sess->responseCode < 400 || sess->responseCode > 599) {
             result = UNSUPPORTED_RESPONSE;

netdiskerror.c

@@ -0,0 +1,129 @@
+#pragma noroot
+
+#include "netdiskerror.h"
+
+char *ErrorString(enum NetDiskError err) {
+    switch (err) {
+    case NETDISK_NOT_PRESENT:
+        return "The NetDisk initialization file was not found. You must have "
+               "NetDiskInit installed in the *:System:System.Setup folder.";
+    case DISK_ALREADY_MOUNTED:
+        return "Tried to mount a disk on a device that is already in use.";
+    case NO_DIBS_AVAILABLE:
+        return "No more disks can be mounted via NetDisk.";
+    case OUT_OF_MEMORY:
+        return "Out of memory.";
+
+    /* SetURL errors */
+    case URL_TOO_LONG:
+        return "The URL is too long.";
+    case INVALID_CHARACTER_IN_URL:
+        return "There was an invalid character in the URL.";
+    case BAD_URL_SYNTAX:
+        return "The URL is invalid.";
+    case UNSUPPORTED_URL_SCHEME:
+        return "Protocols other than unencrypted HTTP are not supported.";
+    case AUTHENTICATION_NOT_SUPPORTED:
+        return "Authentication is not supported.";
+    case FRAGMENT_NOT_SUPPORTED:
+        return "The URL may not specify a document fragment.";
+    case INVALID_PORT_NUMBER:
+        return "The port number is invalid.";
+    case NO_HOST_SPECIFIED:
+        return "No host name or IP address was specified.";
+    case IPV6_NOT_SUPPORTED:
+        return "IPv6 is not supported.";
+    case HOSTNAME_TOO_LONG:
+        return "The specified host name was too long.";
+    case NAME_LOOKUP_FAILED:
+        return "The specified server could not be found.";
+    
+    /* StartTCPConnection and DoHTTPRequest errors */
+    case NETWORK_ERROR:
+        return "A network error was encountered.";
+    case NO_RESPONSE:
+        return "The server did not respond to a request.";
+    case INVALID_RESPONSE:
+        return "The response from the server was invalid.";
+    case EXCESSIVE_REDIRECTS:
+        return "There were too many HTTP redirects.";
+    case UNSUPPORTED_RESPONSE:
+        return "An unsupported response was received from the server.";
+    case UNSUPPORTED_HEADER_VALUE:
+        return "An unsupported header value was received from the server.";
+    case REDIRECT_ERROR:
+        return "An error was encountered when trying to redirect to the "
+               "location specified by the server.";
+    case NOT_DESIRED_CONTENT:
+        return "The server did not send the content that was expected. It may "
+               "not support HTTP range requests, which are required by NetDisk.";
+    case DIFFERENT_LENGTH:
+        return "The length of the file on the server was different from what "
+               "was expected.";
+
+    /* File format errors */
+    case UNSUPPORTED_2IMG_FILE:
+        return "This 2mg file is not supported by NetDisk.";
+    case NOT_MULTIPLE_OF_BLOCK_SIZE:
+        return "The file is not a multiple of 512 bytes. It may not be a disk "
+               "image file, or is not in a supported format.";
+
+    /* HTTP errors */
+    case 400:
+        return "HTTP error 400 (Bad Request) received from server.";
+    case 401:
+        return "HTTP error 401 (Unauthorized) received from server.";
+    case 402:
+        return "HTTP error 402 (Payment Required) received from server.";
+    case 403:
+        return "HTTP error 403 (Forbidden) received from server.";
+    case 404:
+        return "HTTP error 404 (Not Found) received from server.";
+    case 405:
+        return "HTTP error 405 (Method Not Allowed) received from server.";
+    case 406:
+        return "HTTP error 406 (Not Acceptable) received from server.";
+    case 407:
+        return "HTTP error 407 (Proxy Authentication Required) received from server.";
+    case 408:
+        return "HTTP error 408 (Request Timeout) received from server.";
+    case 409:
+        return "HTTP error 409 (Conflict) received from server.";
+    case 410:
+        return "HTTP error 410 (Gone) received from server.";
+    case 411:
+        return "HTTP error 411 (Length Required) received from server.";
+    case 412:
+        return "HTTP error 412 (Precondition Failed) received from server.";
+    case 413:
+        return "HTTP error 413 (Payload Too Large) received from server.";
+    case 414:
+        return "HTTP error 414 (URI Too Long) received from server.";
+    case 415:
+        return "HTTP error 415 (Unsupported Media Type) received from server.";
+    case 416:
+        return "HTTP error 416 (Range Not Satisfiable) received from server.";
+    case 417:
+        return "HTTP error 417 (Expectation Failed) received from server.";
+    case 426:
+        return "HTTP error 426 (Upgrade Required) received from server.";
+    case 500:
+        return "HTTP error 500 (Internal Server Error) received from server.";
+    case 501:
+        return "HTTP error 501 (Not Implemented) received from server.";
+    case 502:
+        return "HTTP error 502 (Bad Gateway) received from server.";
+    case 503:
+        return "HTTP error 503 (Service Unavailable) received from server.";
+    case 504:
+        return "HTTP error 504 (Gateway Timeout) received from server.";
+    case 505:
+        return "HTTP error 505 (HTTP Version Not Supported) received from server.";
+    }
+    
+    if (err >= 400 && err < 600) {
+        return "HTTP error *0 received from server.";
+    }
+    
+    return "NetDisk error *0.";
+}

netdiskerror.h

@@ -42,4 +42,11 @@ enum NetDiskError {
     
 };
 
+
+/*
+ * Return a string describing the error.  It may contain the substitution
+ * string "*0", which should be replaced by the error number.
+ */
+char *ErrorString(enum NetDiskError err);
+
 #endif

session.c

@@ -1,3 +1,5 @@
+#pragma noroot
+
 #include <stdlib.h>
 #include "session.h"
 #include "tcpconnection.h"