= Building NSS on Windows =

== Preamble ==

NSS stands for [http://www.mozilla.org/projects/security/pki/nss/ Network Security Services]. NSS is required to use SSL in Pidgin. NSS depends on NSPR and a [https://wiki.mozilla.org/NSS_Shared_DB shared database] (SQLite since [http://www.mozilla.org/projects/security/pki/nss/nss-3.12/nss-3.12-release-notes.html NSS 3.12]), but you don't have to worry about these, there's and NSS with NSPR package which is compact thus it contains all sources required to build NSS.

'''Note''': at the moment you can't build NSS completely using GCC. It fails at the final stage when linking additional tools. However, you can build all the important libraries successfully. It will hopefully be improved in the future. You can, however, build NSS completely with the Windows Driver Kit, but you'll need the [http://code.google.com/p/xchat-wdk/source/browse/#hg/ext/nss-wdk NSS-WDK patch] (binaries [http://code.google.com/p/xchat-wdk/wiki/InfoNSS here]).

== Prerequisites ==

 1. '''Get the Windows SDK:'''[[BR]]Download the [https://www.microsoft.com/download/en/details.aspx?id=8279 Windows SDK for Windows 7 SP1] and install it to the default location.
 1. '''Get the Windows Driver Kit (WDK):'''[[BR]]Download the [https://www.microsoft.com/download/en/details.aspx?displaylang=en&id=11800 WDK for Windows 7 SP1] and install it to the default location.
 1. '''Get the Netscape Portable Runtime (NSPR):'''[[BR]]Download the latest version of [ftp://ftp.mozilla.org/pub/mozilla.org/nspr/releases/ NSPR] (currently 4.8.9) and extract it to `c:\devel\pidgin-devel\win32-dev`.
 1. '''Get Network Security Services (NSS):'''[[BR]]Download the latest version of [ftp://ftp.mozilla.org/pub/mozilla.org/security/nss/releases/ NSS] (currently 3.12.11 w/ CKBI 1.87) and extract it to the same location.
 1. '''Get MozillaBuild:'''[[BR]]Download the latest version of [ftp://ftp.mozilla.org/pub/mozilla.org/mozilla/libraries/win32/MozillaBuildSetup-Latest.exe MozillaBuild] and install it to `c:\devel\mozilla-build`.

== Choose build configuration ==

The two most important options are:

 * optimization
 * debug RTL

You can toggle them with environmental variables. Here's the matrix:
   {{{
#!rst
+-----------+----------------+-----------------+
|           |USE_DEBUG_RTL=  |USE_DEBUG_RTL=1  |
+===========+================+=================+
|BUILD_OPT= |WINNT6.1_DBG.OBJ|WINNT6.1_DBG.OBJD|
+-----------+----------------+-----------------+
|BUILD_OPT=1|WINNT6.1_OPT.OBJ|N/A              |
+-----------+----------------+-----------------+
   }}}

The version after WINNT is the version of your current OS (you can check it with the `winver` command). WINNT6.1 assumes you're building on Windows 7. The default setting is an unoptimized build with the release RTL (WINNT6.1_DBG.OBJ).

'''WARNING''': it seems the builder considers any variable as 1 if it's set. So if you enter
   {{{
set BUILD_OPT=0
   }}}
you'll get an optimized build although you wanted a debug one. The answer lies in `mozilla\security\coreconf\WIN32.mk`. They check variables with ifdefs, which is just plain wrong (or they should mention it this way in the documentation).

'''Solution''': set a variable only if you want the related build. Here's the table for seeing what you actually have to enter and what you'll get:
   || || ||USE_DEBUG_RTL=1||BUILD_OPT=1||
   ||OS_TARGET=WIN95||WIN954.0_DBG.OBJ||WIN954.0_DBG.OBJD||WIN954.0_OPT.OBJ||
   ||OS_TARGET=WINNT||WINNT6.1_DBG.OBJ||WINNT6.1_DBG.OBJD||WINNT6.1_OPT.OBJ||
OS_TARGET is an exception and isn't affected by this error because it's not numerical, so the script checks for its value instead of its existence. As a sidenote, BUILD_OPT seems to have a higher priority than USE_DEBUG_RTL, so if you enter
   {{{
set BUILD_OPT=1
set USE_DEBUG_RTL=1
   }}}
you'll get an optimized build without linking with the debug RTL. In case you want, for example, a debug build after an optimized, you can unset the variable by setting it without a value, such as:

   {{{
set BUILD_OPT=
   }}}

More info about the build variables can be found on the [https://developer.mozilla.org/en/NSS_reference/Building_and_installing_NSS/Build_instructions Build instructions] page of the Mozilla Developer Central.

== Build NSS ==

The easiest way to do this with consistent results is to make a build script (the following is what the binary included with Pidgin is built with):
{{{
#!sh
#!/bin/bash

#The path that we've extracted the nss source tarball into
NSS_SRC_DIR=/c/devel/pidgin-devel/win32-dev

#Set our Build Arguments:
#Optimized Build
export BUILD_OPT=1
#Target Windows NT Family
export OS_TARGET=WINNT
#Use GCC (as opposed to VC)
export NS_USE_GCC=1

#Set up the build path with MinGW and Moztools
PATH=/c/devel/pidgin-devel/win32-dev/mingw/bin
PATH=/c/devel/mozilla-build/moztools/bin:$PATH
PATH=/c/devel/mozilla-build/msys/bin:$PATH
export PATH

pushd $NSS_SRC_DIR/nss-3.12.8/mozilla/security/nss
make nss_build_all
popd

}}}

Save this script as `build.sh`. Launch a command prompt and run:

{{{
c:\devel\mozilla-build\msys\bin\sh build.sh
}}}

The build will likely not complete successfully due to hardcoded library paths and other problems in the build system (it will bail out building `.../cmd/bltest`).  If it gets that far, it has already built the various libraries successfully.

The resulting binaries will be placed in `c:\devel\pidgin-devel\win32-dev\nss-3.12.8\mozilla\dist`. The contents of `private` and `public` are the same across all configurations so they can be distributed separately.