doc: complete windows.md

This adds more explanations and explain how to properly build with and without Cygwin.

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>

docs/windows.md

@@ -16,6 +16,13 @@ the Path environment variable.
 Please install the Go language as explained on
 https://golang.org/doc/install.
 
+To properly install Go, you will need to set some environment
+variables. We recommend you to set them globally using the Control
+Panel, as explained in the documentation above, so that these
+environment variables are automatically available in all the possible
+environments that you might want to use like Git Bash, Windows's cmd,
+Cygwin's terminal, Windows' PowerShell and so on.
+
 You must make sure that the GOROOT environment variable is set and
 that the %GOROOT%/bin directory is in the Path environment variable.
 
@@ -23,36 +30,113 @@ The GOPATH environment variable should also be set to a directory that
 you have created, and the %GOPATH/bin directory should also be in the
 Path environment variable.
 
-## Download go-ipfs and its dependencies
+## Download go-ipfs and fix Git authentication
 
-The following commands should download or update go-ipfs and its
-dependencies:
+Use the following command to download go-ipfs source code:
 
-```sh
-go get -u github.com/whyrusleeping/gx
-go get -u github.com/whyrusleeping/gx-go
+```
 go get -u github.com/ipfs/go-ipfs
-cd %GOPATH%/src/github.com/ipfs/go-ipfs
-gx --verbose install --global
 ```
 
-If you get authentication problems with Git, you might want to take a
-look at
+The above command uses Git to download go-ipfs from its GitHub
+repository. If you get authentication problems with Git, you might
+want to take a look at
 https://help.github.com/articles/caching-your-github-password-in-git/
 and use the suggested solution:
 
-```sh
+```
 git config --global credential.helper wincred
 ```
 
-## Build
+## Choose the way you want to proceed
+
+Now there are two ways to download, install the dependencies and to
+build go-ipfs:
+
+1) There is the "Manual Way", where you don't need to install anymore
+software except the dependencies, but you have a number of commands to
+type.
+
+2) There is a way by installing 'make' through Cygwin and using it to
+do nearly everything. We call this way the "Cygwin Way". It may take
+much more time, because installing Cygwin can take a lot of time, but
+after that it might be easier as many procedures are just a 'make'
+command away.
+
+So use the next steps below that start with "Manual Way" if that's the
+way you want, otherwise scroll down a bit and use the "Cygwin Way"
+steps below.
+
+## Manual Way: download and install dependencies
+
+The following commands should download or update go-ipfs dependencies
+and then install them:
+
+```
+go get -u github.com/whyrusleeping/gx
+go get -u github.com/whyrusleeping/gx-go
+cd %GOPATH%/src/github.com/ipfs/go-ipfs
+gx --verbose install --global
+```
+
+## Manual Way: build go-ipfs
+
+To actually build go-ipfs, first go to the cmd/ipfs directory:
+
+```
+cd cmd\ipfs
+```
+
+Then get the current Git commit:
+
+```
+git rev-parse --short HEAD
+```
+
+It will output a small number of hex characters that you must pass to
+the actual build command (replace XXXXXXX with these characters):
+
+```
+go install -ldflags="-X "github.com/ipfs/go-ipfs/repo/config".CurrentCommit=XXXXXXX"
+```
+
+After that ipfs should have been built and should be available in
+"%GOPATH%\bin".
+
+You can check that the ipfs you built has the right version using:
+
+```
+ipfs version --commit
+```
+
+It should output something like "ipfs version 0.4.0-dev-XXXXXXX" where
+XXXXXXX is the current commit that you passed to the build command.
+
+## Cygwin way: install Cygwin
+
+Install Cygwin as explained in the Cygwin documentation:
+
+http://cygwin.com/install.html
 
-Fuse is not supported for Windows, so you need to build IPFS without Fuse:
+By default Cygwin will not install 'make', so you should click on the
+"Devel" category during the Cygwin installation process and then check
+the 'make' package.
 
-```sh
-go build -tags nofuse ./cmd/ipfs
+## Cygwin way: build go-ipfs
+
+To build go-ipfs using Cygwin you just need to open a Cygwin Terminal
+and then type the following commands:
+
+```
+cd $GOPATH/src/github.com/ipfs/go-ipfs
+make install
 ```
 
-## TODO
+After that ipfs should have been built and should be available in
+"%GOPATH%\bin".
 
-Fix the "Build" section to pass the current commit as the Makefile does.
+You can check that the ipfs you built has the right version using:
+
+```
+ipfs version --commit
+```