/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set ts=4 sw=4 sts=4 ci et: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Darin Fisher <darin@netscape.com> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
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 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsHttpHeaderArray.h"
#include "nsHttp.h"

//-----------------------------------------------------------------------------
// nsHttpHeaderArray <public>
//-----------------------------------------------------------------------------

nsresult
nsHttpHeaderArray::SetHeader(nsHttpAtom header,
                             const nsACString &value,
                             PRBool merge)
{
    nsEntry *entry = nsnull;
    PRInt32 index;

    index = LookupEntry(header, &entry);

    // If an empty value is passed in, then delete the header entry...
    // unless we are merging, in which case this function becomes a NOP.
    if (value.IsEmpty()) {
        if (!merge && entry)
            mHeaders.RemoveElementAt(index);
        return NS_OK;
    }

    // Create a new entry, or...
    if (!entry) {
        entry = mHeaders.AppendElement(); //new nsEntry(header, value);
        if (!entry)
            return NS_ERROR_OUT_OF_MEMORY;
        entry->header = header;
        entry->value = value;
    }
    // Append the new value to the existing value iff...
    else if (merge && CanAppendToHeader(header)) {
        if (header == nsHttp::Set_Cookie ||
            header == nsHttp::WWW_Authenticate ||
            header == nsHttp::Proxy_Authenticate)
            // Special case these headers and use a newline delimiter to
            // delimit the values from one another as commas may appear
            // in the values of these headers contrary to what the spec says.
            entry->value.Append('\n');
        else
            // Delimit each value from the others using a comma (per HTTP spec)
            entry->value.AppendLiteral(", ");
        entry->value.Append(value);
    }
    // Replace the existing string with the new value
    else if (CanOverwriteHeader(header))
        entry->value = value;
    else if (!entry->value.Equals(value))
        return NS_ERROR_CORRUPTED_CONTENT;

    return NS_OK;
}

void
nsHttpHeaderArray::ClearHeader(nsHttpAtom header)
{
    mHeaders.RemoveElement(header, nsEntry::MatchHeader());
}

const char *
nsHttpHeaderArray::PeekHeader(nsHttpAtom header)
{
    nsEntry *entry = nsnull;
    LookupEntry(header, &entry);
    return entry ? entry->value.get() : nsnull;
}

nsresult
nsHttpHeaderArray::GetHeader(nsHttpAtom header, nsACString &result)
{
    nsEntry *entry = nsnull;
    LookupEntry(header, &entry);
    if (!entry)
        return NS_ERROR_NOT_AVAILABLE;
    result = entry->value;
    return NS_OK;
}

nsresult
nsHttpHeaderArray::VisitHeaders(nsIHttpHeaderVisitor *visitor)
{
    NS_ENSURE_ARG_POINTER(visitor);
    PRUint32 i, count = mHeaders.Length();
    for (i = 0; i < count; ++i) {
        const nsEntry &entry = mHeaders[i];
        if (NS_FAILED(visitor->VisitHeader(nsDependentCString(entry.header),
                                           entry.value)))
            break;
    }
    return NS_OK;
}

nsresult
nsHttpHeaderArray::ParseHeaderLine(const char *line,
                                   nsHttpAtom *hdr,
                                   char **val)
{
    //
    // BNF from section 4.2 of RFC 2616:
    //
    //   message-header = field-name ":" [ field-value ]
    //   field-name     = token
    //   field-value    = *( field-content | LWS )
    //   field-content  = <the OCTETs making up the field-value
    //                     and consisting of either *TEXT or combinations
    //                     of token, separators, and quoted-string>
    //
    
    // We skip over mal-formed headers in the hope that we'll still be able to
    // do something useful with the response.

    char *p = (char *) strchr(line, ':');
    if (!p) {
        LOG(("malformed header [%s]: no colon\n", line));
        return NS_OK;
    }

    // make sure we have a valid token for the field-name
    if (!nsHttp::IsValidToken(line, p)) {
        LOG(("malformed header [%s]: field-name not a token\n", line));
        return NS_OK;
    }
    
    *p = 0; // null terminate field-name

    nsHttpAtom atom = nsHttp::ResolveAtom(line);
    if (!atom) {
        LOG(("failed to resolve atom [%s]\n", line));
        return NS_OK;
    }

    // skip over whitespace
    p = net_FindCharNotInSet(++p, HTTP_LWS);

    // trim trailing whitespace - bug 86608
    char *p2 = net_RFindCharNotInSet(p, HTTP_LWS);

    *++p2 = 0; // null terminate header value; if all chars starting at |p|
               // consisted of LWS, then p2 would have pointed at |p-1|, so
               // the prefix increment is always valid.

    // assign return values
    if (hdr) *hdr = atom;
    if (val) *val = p;

    // assign response header
    return SetHeader(atom, nsDependentCString(p, p2 - p), PR_TRUE);
}

void
nsHttpHeaderArray::Flatten(nsACString &buf, PRBool pruneProxyHeaders)
{
    PRUint32 i, count = mHeaders.Length();
    for (i = 0; i < count; ++i) {
        const nsEntry &entry = mHeaders[i];
        // prune proxy headers if requested
        if (pruneProxyHeaders && ((entry.header == nsHttp::Proxy_Authorization) || 
                                  (entry.header == nsHttp::Proxy_Connection)))
            continue;
        buf.Append(entry.header);
        buf.AppendLiteral(": ");
        buf.Append(entry.value);
        buf.AppendLiteral("\r\n");
    }
}

const char *
nsHttpHeaderArray::PeekHeaderAt(PRUint32 index, nsHttpAtom &header)
{
    const nsEntry &entry = mHeaders[index];

    header = entry.header;
    return entry.value.get();
}

void
nsHttpHeaderArray::Clear()
{
    mHeaders.Clear();
}

//-----------------------------------------------------------------------------
// nsHttpHeaderArray <private>
//-----------------------------------------------------------------------------

PRInt32
nsHttpHeaderArray::LookupEntry(nsHttpAtom header, nsEntry **entry)
{
    PRUint32 index = mHeaders.IndexOf(header, 0, nsEntry::MatchHeader());
    if (index != PR_UINT32_MAX)
      *entry = &mHeaders[index];
    return index;
}

PRBool
nsHttpHeaderArray::CanAppendToHeader(nsHttpAtom header)
{
    return header != nsHttp::Content_Type        &&
           header != nsHttp::Content_Length      &&
           header != nsHttp::User_Agent          &&
           header != nsHttp::Referer             &&
           header != nsHttp::Host                &&
           header != nsHttp::Authorization       &&
           header != nsHttp::Proxy_Authorization &&
           header != nsHttp::If_Modified_Since   &&
           header != nsHttp::If_Unmodified_Since &&
           header != nsHttp::From                &&
           header != nsHttp::Location            &&
           header != nsHttp::Max_Forwards;
}

PRBool
nsHttpHeaderArray::CanOverwriteHeader(nsHttpAtom header)
{
    if (mType != HTTP_RESPONSE_HEADERS)
        return PR_TRUE;
    return header != nsHttp::Content_Length;
}