Status code (TDStatus) overhaul

* Use symbolic constants for codes, i.e. kTDStatusNotFound instead of 404.
* Add extra, more detailed status codes and map them to custom response messages.

Listener/TDHTTPResponse.m

@@ -195,26 +195,21 @@ - (void) onFinished {
             // to massage the response:
             LogTo(TDListenerVerbose, @"%@ prettifying response body", self);
             int status = _response.status;
-            if (status >= 300 && _data.length == 0) {
-                // Put a generic error message in the body:
+            if (TDStatusIsError(status) && _data.length == 0) {
+                // Put an error message in the body:
                 NSString* errorMsg;
-                switch (status) {
-                    case 404:   errorMsg = @"not_found"; break;
-                        // TODO: There are more of these to add; see error_info() in couch_httpd.erl
-                    default:
-                        errorMsg = [NSHTTPURLResponse localizedStringForStatusCode: status];
-                }
+                status = _response.status = TDStatusToHTTPStatus(status, &errorMsg);
                 NSString* responseStr = [NSString stringWithFormat: @"{\"status\": %i, \"error\":\"%@\"}\n",
                                                                      status, errorMsg];
                 [_response.headers setObject: @"text/plain; encoding=UTF-8" forKey: @"Content-Type"];
                 [self onDataAvailable: [responseStr dataUsingEncoding: NSUTF8StringEncoding]
                              finished: NO];
             } else {
-    #if DEBUG
+#if DEBUG
                 BOOL pretty = YES;
-    #else
+#else
                 BOOL pretty = [_router boolQuery: @"pretty"];
-    #endif
+#endif
                 if (pretty) {
                     [_data release];
                     _data = [_response.body.asPrettyJSON mutableCopy];

Source/ChangeTracker/TDChangeTracker.m

@@ -19,6 +19,7 @@
 #import "TDConnectionChangeTracker.h"
 #import "TDSocketChangeTracker.h"
 #import "TDMisc.h"
+#import "TDStatus.h"
 
 
 @interface TDChangeTracker ()
@@ -118,7 +119,7 @@ - (NSURLCredential*) authCredential {
 
 - (void) setUpstreamError: (NSString*)message {
     Warn(@"%@: Server error: %@", self, message);
-    self.error = [NSError errorWithDomain: @"TDChangeTracker" code: 502 userInfo: nil];
+    self.error = [NSError errorWithDomain: @"TDChangeTracker" code: kTDStatusUpstreamError userInfo: nil];
 }
 
 - (BOOL) start {

Source/ChangeTracker/TDConnectionChangeTracker.m

@@ -17,6 +17,7 @@
 
 #import "TDConnectionChangeTracker.h"
 #import "TDMisc.h"
+#import "TDStatus.h"
 
 
 @implementation TDConnectionChangeTracker
@@ -79,11 +80,11 @@ - (void)connection:(NSURLConnection *)connection
 }
 
 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
-    int status = (int) ((NSHTTPURLResponse*)response).statusCode;
+    TDStatus status = (TDStatus) ((NSHTTPURLResponse*)response).statusCode;
     LogTo(ChangeTracker, @"%@: Got response, status %d", self, status);
-    if (status >= 300) {
+    if (TDStatusIsError(status)) {
         Warn(@"%@: Got status %i", self, status);
-        self.error = TDHTTPError(status, self.changesFeedURL);
+        self.error = TDStatusToNSError(status, self.changesFeedURL);
         [self stop];
     }
 }

Source/ChangeTracker/TDRemoteRequest.h

@@ -34,7 +34,7 @@ typedef void (^TDRemoteRequestCompletionBlock)(id result, NSError* error);
 - (id) initWithMethod: (NSString*)method URL: (NSURL*)url body: (id)body
          onCompletion: (TDRemoteRequestCompletionBlock)onCompletion;
 
-/** In some cases a 404 Not Found is an expected condition and shouldn't be logged; call this to suppress that log message. */
+/** In some cases a kTDStatusNotFound Not Found is an expected condition and shouldn't be logged; call this to suppress that log message. */
 - (void) dontLog404;
 
 // protected:

Source/ChangeTracker/TDRemoteRequest.m

@@ -17,6 +17,7 @@
 #import "TDMisc.h"
 #import "TDMultipartReader.h"
 #import "TDBlobStore.h"
+#import "TDDatabase.h"
 
 
 // Max number of retry attempts for a transient failure
@@ -100,7 +101,7 @@ - (void) cancelWithStatus: (int)status {
         return;
     }
 
-    [self connection: _connection didFailWithError: TDHTTPError(status, _request.URL)];
+    [self connection: _connection didFailWithError: TDStatusToNSError(status, _request.URL)];
 }
 
 
@@ -110,7 +111,7 @@ - (void) cancelWithStatus: (int)status {
 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
     int status = (int) ((NSHTTPURLResponse*)response).statusCode;
     LogTo(RemoteRequest, @"%@: Got response, status %d", self, status);
-    if (status >= 300) 
+    if (TDStatusIsError(status)) 
         [self cancelWithStatus: status];
 }
 
@@ -120,7 +121,7 @@ - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
 
 - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
     if (WillLog()) {
-        if (!(_dontLog404 && error.code == 404 && $equal(error.domain, TDHTTPErrorDomain)))
+        if (!(_dontLog404 && error.code == kTDStatusNotFound && $equal(error.domain, TDHTTPErrorDomain)))
             Log(@"%@: Got error %@", self, error);
     }
     [self clearConnection];
@@ -174,7 +175,7 @@ - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
     if (!result) {
         Warn(@"%@: %@ %@ returned unparseable data '%@'",
              self, _request.HTTPMethod, _request.URL, [_jsonBuffer my_UTF8ToString]);
-        error = TDHTTPError(502, _request.URL);
+        error = TDStatusToNSError(kTDStatusUpstreamError, _request.URL);
     }
     [self clearConnection];
     [self respondWithResult: result error: error];

Source/TDDatabase+Attachments.m

@@ -93,9 +93,9 @@ - (TDStatus) insertAttachment: (TDAttachment*)attachment
                                  attachment.contentType, $object(attachment->encoding),
                                  $object(attachment->length), encodedLengthObj,
                                  $object(attachment->revpos)]) {
-        return 500;
+        return kTDStatusDBError;
     }
-    return 201;
+    return kTDStatusCreated;
 }
 
 
@@ -107,23 +107,23 @@ - (TDStatus) copyAttachmentNamed: (NSString*)name
     Assert(toSequence > 0);
     Assert(toSequence > fromSequence);
     if (fromSequence <= 0)
-        return 404;
+        return kTDStatusNotFound;
     if (![_fmdb executeUpdate: @"INSERT INTO attachments "
                     "(sequence, filename, key, type, encoding, encoded_Length, length, revpos) "
                     "SELECT ?, ?, key, type, encoding, encoded_Length, length, revpos "
                         "FROM attachments WHERE sequence=? AND filename=?",
                     $object(toSequence), name,
                     $object(fromSequence), name]) {
-        return 500;
+        return kTDStatusDBError;
     }
     if (_fmdb.changes == 0) {
         // Oops. This means a glitch in our attachment-management or pull code,
         // or else a bug in the upstream server.
         Warn(@"Can't find inherited attachment '%@' from seq#%lld to copy to #%lld",
              name, fromSequence, toSequence);
-        return 404;         // Fail if there is no such attachment on fromSequence
+        return kTDStatusNotFound;         // Fail if there is no such attachment on fromSequence
     }
-    return 200;
+    return kTDStatusOK;
 }
 
 
@@ -150,29 +150,32 @@ - (NSData*) getAttachmentForSequence: (SequenceNumber)sequence
     Assert(sequence > 0);
     Assert(filename);
     NSData* contents = nil;
-    *outStatus = 500;
     FMResultSet* r = [_fmdb executeQuery:
                       @"SELECT key, type, encoding FROM attachments WHERE sequence=? AND filename=?",
                       $object(sequence), filename];
-    if (!r)
+    if (!r) {
+        *outStatus = kTDStatusDBError;
         return nil;
+    }
     @try {
         if (![r next]) {
-            *outStatus = 404;
+            *outStatus = kTDStatusNotFound;
             return nil;
         }
         NSData* keyData = [r dataNoCopyForColumnIndex: 0];
         if (keyData.length != sizeof(TDBlobKey)) {
             Warn(@"%@: Attachment %lld.'%@' has bogus key size %d",
                  self, sequence, filename, keyData.length);
+            *outStatus = kTDStatusCorruptError;
             return nil;
         }
         contents = [_attachments blobForKey: *(TDBlobKey*)keyData.bytes];
         if (!contents) {
             Warn(@"%@: Failed to load attachment %lld.'%@'", self, sequence, filename);
+            *outStatus = kTDStatusCorruptError;
             return nil;
         }
-        *outStatus = 200;
+        *outStatus = kTDStatusOK;
         if (outType)
             *outType = [r stringForColumnIndex: 1];
 
@@ -320,35 +323,31 @@ - (NSDictionary*) attachmentsFromRevision: (TDRevision*)rev
     // If there are no attachments in the new rev, there's nothing to do:
     NSDictionary* revAttachments = [rev.properties objectForKey: @"_attachments"];
     if (revAttachments.count == 0 || rev.deleted) {
-        *outStatus = 200;
+        *outStatus = kTDStatusOK;
         return [NSDictionary dictionary];
     }
 
-    TDStatus status = 200;
+    TDStatus status = kTDStatusOK;
     NSMutableDictionary* attachments = $mdict();
     for (NSString* name in revAttachments) {
         // Create a TDAttachment object:
         NSDictionary* attachInfo = [revAttachments objectForKey: name];
         NSString* contentType = $castIf(NSString, [attachInfo objectForKey: @"content_type"]);
         TDAttachment* attachment = [[[TDAttachment alloc] initWithName: name
                                                            contentType: contentType] autorelease];
-        if (!attachment) {
-            status = 500;
-            break;
-        }
 
         NSString* newContentsBase64 = $castIf(NSString, [attachInfo objectForKey: @"data"]);
         if (newContentsBase64) {
             // If there's inline attachment data, decode and store it:
             @autoreleasepool {
                 NSData* newContents = [TDBase64 decode: newContentsBase64];
                 if (!newContents) {
-                    status = 400;
+                    status = kTDStatusBadEncoding;
                     break;
                 }
                 attachment->length = newContents.length;
                 if (![self storeBlob: newContents creatingKey: &attachment->blobKey]) {
-                    status = 500;
+                    status = kTDStatusAttachmentError;
                     break;
                 }
             }
@@ -358,11 +357,11 @@ - (NSDictionary*) attachmentsFromRevision: (TDRevision*)rev
             // I just need to look it up by its "digest" property and install it into the store:
             TDBlobStoreWriter *writer = [self attachmentWriterForAttachment: attachInfo];
             if (!writer) {
-                status = 400;
+                status = kTDStatusBadAttachment;
                 break;
             }
             if (![writer install]) {
-                status = 500;
+                status = kTDStatusAttachmentError;
                 break;
             }
             attachment->blobKey = writer.blobKey;
@@ -378,7 +377,7 @@ - (NSDictionary*) attachmentsFromRevision: (TDRevision*)rev
             if ($equal(encodingStr, @"gzip"))
                 attachment->encoding = kTDAttachmentEncodingGZIP;
             else {
-                status = 400;
+                status = kTDStatusBadEncoding;
                 break;
             }
 
@@ -404,7 +403,7 @@ - (TDStatus) processAttachments: (NSDictionary*)attachments
     // If there are no attachments in the new rev, there's nothing to do:
     NSDictionary* revAttachments = [rev.properties objectForKey: @"_attachments"];
     if (revAttachments.count == 0 || rev.deleted)
-        return 200;
+        return kTDStatusOK;
 
     SequenceNumber newSequence = rev.sequence;
     Assert(newSequence > 0);
@@ -421,7 +420,7 @@ - (TDStatus) processAttachments: (NSDictionary*)attachments
             if (attachment->revpos == 0)
                 attachment->revpos = generation;
             else if (attachment->revpos > generation)
-                return 400;
+                return kTDStatusBadAttachment;
 
             // Finally insert the attachment:
             status = [self insertAttachment: attachment forSequence: newSequence];
@@ -432,10 +431,10 @@ - (TDStatus) processAttachments: (NSDictionary*)attachments
                                   fromSequence: parentSequence
                                     toSequence: newSequence];
         }
-        if (status >= 300)
+        if (TDStatusIsError(status))
             return status;
     }
-    return 200;
+    return kTDStatusOK;
 }
 
 
@@ -469,7 +468,7 @@ - (TDRevision*) updateAttachment: (NSString*)filename
                            revID: (NSString*)oldRevID
                           status: (TDStatus*)outStatus
 {
-    *outStatus = 400;
+    *outStatus = kTDStatusBadAttachment;
     if (filename.length == 0 || (body && !contentType) || (oldRevID && !docID) || (body && !docID))
         return nil;
 
@@ -479,14 +478,14 @@ - (TDRevision*) updateAttachment: (NSString*)filename
         if (oldRevID) {
             // Load existing revision if this is a replacement:
             *outStatus = [self loadRevisionBody: oldRev options: 0];
-            if (*outStatus >= 300) {
-                if (*outStatus == 404 && [self existsDocumentWithID: docID revisionID: nil])
-                    *outStatus = 409;   // if some other revision exists, it's a conflict
+            if (TDStatusIsError(*outStatus)) {
+                if (*outStatus == kTDStatusNotFound && [self existsDocumentWithID: docID revisionID: nil])
+                    *outStatus = kTDStatusConflict;   // if some other revision exists, it's a conflict
                 return nil;
             }
             NSDictionary* attachments = [oldRev.properties objectForKey: @"_attachments"];
             if (!body && ![attachments objectForKey: filename]) {
-                *outStatus = 404;
+                *outStatus = kTDStatusAttachmentNotFound;
                 return nil;
             }
             // Remove the _attachments stubs so putRevision: doesn't copy the rows for me
@@ -516,7 +515,7 @@ - (TDRevision*) updateAttachment: (NSString*)filename
                     "FROM attachments WHERE sequence=? AND filename != ?",
                                         $object(newRev.sequence), $object(oldRev.sequence),
                                         filename]) {
-                *outStatus = 500;
+                *outStatus = kTDStatusDBError;
                 return nil;
             }
         }
@@ -533,22 +532,22 @@ - (TDRevision*) updateAttachment: (NSString*)filename
                 attachment->encodedLength = attachment->length;
                 attachment->length = [self decodeAttachment: body encoding: encoding].length;
                 if (attachment->length == 0 && attachment->encodedLength > 0) {
-                    *outStatus = 400;     // failed to decode
+                    *outStatus = kTDStatusBadEncoding;     // failed to decode
                     return nil;
                 }
             }
 
             if (![self storeBlob: body creatingKey: &attachment->blobKey]) {
-                *outStatus = 500;
+                *outStatus = kTDStatusAttachmentError;
                 return nil;
             }
 
             *outStatus = [self insertAttachment: attachment forSequence: newRev.sequence];
-            if (*outStatus >= 300)
+            if (TDStatusIsError(*outStatus))
                 return nil;
         }
 
-        *outStatus = body ? 201 : 200;
+        *outStatus = body ? kTDStatusCreated : kTDStatusOK;
         return newRev;
     } @finally {
         [self endTransaction: (*outStatus < 300)];
@@ -565,17 +564,17 @@ - (TDStatus) garbageCollectAttachments {
     // Now collect all remaining attachment IDs and tell the store to delete all but these:
     FMResultSet* r = [_fmdb executeQuery: @"SELECT DISTINCT key FROM attachments"];
     if (!r)
-        return 500;
+        return kTDStatusDBError;
     NSMutableSet* allKeys = [NSMutableSet set];
     while ([r next]) {
         [allKeys addObject: [r dataForColumnIndex: 0]];
     }
     [r close];
     NSInteger numDeleted = [_attachments deleteBlobsExceptWithKeys: allKeys];
     if (numDeleted < 0)
-        return 500;
+        return kTDStatusAttachmentError;
     Log(@"Deleted %d attachments", numDeleted);
-    return 200;
+    return kTDStatusOK;
 }
 
 

Source/TDDatabase+Insertion.h

@@ -24,7 +24,7 @@ typedef BOOL (^TDValidationBlock) (TDRevision* newRevision,
 /** Stores a new (or initial) revision of a document. This is what's invoked by a PUT or POST. As with those, the previous revision ID must be supplied when necessary and the call will fail if it doesn't match.
     @param revision  The revision to add. If the docID is nil, a new UUID will be assigned. Its revID must be nil. It must have a JSON body.
     @param prevRevID  The ID of the revision to replace (same as the "?rev=" parameter to a PUT), or nil if this is a new document.
-    @param allowConflict  If NO, an error status 409 will be returned if the insertion would create a conflict, i.e. if the previous revision already has a child.
+    @param allowConflict  If NO, an error status kTDStatusConflict will be returned if the insertion would create a conflict, i.e. if the previous revision already has a child.
     @param status  On return, an HTTP status code indicating success or failure.
     @return  A new TDRevision with the docID, revID and sequence filled in (but no body). */
 - (TDRevision*) putRevision: (TDRevision*)revision