Add download git support.

Add support to use a git cloned repo as the source. Move the download
code out of the build module and into a separate module. Add to this
module support for git.

Update the GCC common configuration to support using a symlinked
git repo.

Add checks for all languages.

5 files changed, 397 insertions, 155 deletions

diff --git a/source-builder/config/checks.cfg b/source-builder/config/checks.cfg
index eaa8d93..11a8d67 100644
--- a/source-builder/config/checks.cfg
+++ b/source-builder/config/checks.cfg
@@ -18,9 +18,43 @@
 %endif
 
 #
+# Default to Ada off.
+#
+%ifn %{defined enable_ada}
+%define enable_ada 0
+%endif
+
+#
+# Default to Go off.
+#
+%ifn %{defined enable_go}
+%define enable_go 0
+%endif
+
+#
+# Default to Fortran off.
+#
+%ifn %{defined enable_fortran}
+%define enable_fortran 0
+%endif
+
+#
+# Default to Java off.
+#
+%ifn %{defined enable_java}
+%define enable_java 0
+%endif
+
+#
+# Default to ObjC off.
+#
+%ifn %{defined enable_objc}
+%define enable_objc 0
+%endif
+
+#
 # Hack to get around the ARM EABBI mess.
 #
 %ifn %{defined enable_obsolete}
 %define enable_obsolete 0
 %endif
-
diff --git a/source-builder/config/gcc-common-1.cfg b/source-builder/config/gcc-common-1.cfg
index 6a3c5c1..e1d046e 100644
--- a/source-builder/config/gcc-common-1.cfg
+++ b/source-builder/config/gcc-common-1.cfg
@@ -33,9 +33,10 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
 #
 %prep
   # gcc and optional the g++ core if separate packages
+  source_dir_0="gcc-%{gcc_version}"
   %setup -q -c -n %{name}-%{version}
   %{?source1:%setup -q -D -T -n %{name}-%{version} -a1}
-  cd gcc-%{gcc_version}
+  cd ${source_dir_0}
   %{?patch0:%patch0 %{?patch0_opts:%{patch0_opts}}%{!?patch0_opts:-p1}}
   %{?patch1:%patch1 %{?patch1_opts:%{patch1_opts}}%{!?patch1_opts:-p1}}
   %{?patch2:%patch2 %{?patch2_opts:%{patch2_opts}}%{!?patch2_opts:-p1}}
@@ -49,8 +50,9 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   cd ..
 
   # newlib
+  source_dir_10="newlib-%{newlib_version}"
   %setup -q -D -T -n %{name}-%{version} -a10
-  cd newlib-%{newlib_version}
+  cd ${source_dir_10}
   %{?patch10:%patch10 %{?patch10_opts:%{patch10_opts}}%{!?patch10_opts:-p1}}
   %{?patch11:%patch11 %{?patch11_opts:%{patch11_opts}}%{!?patch11_opts:-p1}}
   %{?patch12:%patch12 %{?patch12_opts:%{patch12_opts}}%{!?patch12_opts:-p1}}
@@ -64,40 +66,48 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   cd ..
 
   # Link newlib into the gcc source tree
-  ln -s ../newlib-%{newlib_version}/newlib gcc-%{gcc_version}
+  %{__rmfile} ${source_dir_0}/newlib
+  %{__ln_s} $PWD/${source_dir_10}/newlib ${source_dir_0}/newlib
 
   # MPFR
+  source_dir_20="mpfr-%{mpfr_version}"
   %setup -q -D -T -n %{name}-%{version} -a20
-  cd mpfr-%{mpfr_version}
+  cd ${source_dir_20}
   %{?patch20:%patch20 -p1}
   cd ..
   # Build MPFR one-tree style
-  ln -s ../mpfr-%{mpfr_version} gcc-%{gcc_version}/mpfr
+  %{__rmfile} ${source_dir_0}/mpfr
+  %{__ln_s} $PWD/${source_dir_20} ${source_dir_0}/mpfr
 
   # MPC
+  source_dir_21="mpc-%{mpc_version}"
   %setup -q -D -T -n %{name}-%{version} -a21
-  cd mpc-%{mpc_version}
+  cd ${source_dir_21}
   %{?patch21:%patch21 -p1}
   cd ..
   # Build MPC one-tree style
-  ln -s ../mpc-%{mpc_version} gcc-%{gcc_version}/mpc
+  %{__rmfile} ${source_dir_0}/mpc
+  %{__ln_s} $PWD/${source_dir_21} ${source_dir_0}/mpc
 
   # GMP
+  source_dir_22="gmp-%{gmp_version}"
   %setup -q -D -T -n %{name}-%{version} -a22
-  cd gmp-%{gmp_version}
+  cd ${source_dir_22}
   %{?patch22:%patch22 -p1}
   cd ..
   # Build GMP one-tree style
-  ln -s ../gmp-%{gmp_version} gcc-%{gcc_version}/gmp
+  %{__rmfile} ${source_dir_0}/gmp
+  %{__ln_s} $PWD/${source_dir_22} ${source_dir_0}/gmp
 
-  echo "%{gcc_version_message}" > gcc-%{gcc_version}/gcc/DEV-PHASE
+  echo "%{gcc_version_message}" > ${source_dir_0}/gcc/DEV-PHASE
 
   # Fix timestamps
-  cd gcc-%{gcc_version}
+  cd ${source_dir_0}
   contrib/gcc_update --touch
   cd ..
 
 %build
+  # Build directory support.
   if test "%{_build}" != "%{_host}" ; then
     build_dir="build-cxc"
   else
@@ -105,10 +115,29 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   fi
   mkdir -p ${build_dir}
   cd ${build_dir}
+
+  # Languages.
   languages="c"
 %if %{enable_cxx}
   languages="$languages,c++"
 %endif
+%if %{enable_ada}
+  languages="$languages,ada"
+%endif
+%if %{enable_go}
+  languages="$languages,go"
+%endif
+%if %{enable_fortran}
+  languages="$languages,fortran"
+%endif
+%if %{enable_java}
+  languages="$languages,java"
+%endif
+%if %{enable_objc}
+  languages="$languages,objc"
+%endif
+
+  # Host flags
   if test "%{_build}" != "%{_host}" ; then
     CFLAGS_FOR_BUILD="-g -O2 -Wall"
     CC="%{_host}-gcc ${SB_OPT_FLAGS}"
@@ -120,7 +149,8 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
     CXX=$(echo "%{__cxx} ${SB_OPT_FLAGS}" | sed -e 's,-std=gnu99 ,,')
   fi
   export CFLAGS CFLAGS_FOR_BUILD CC CXXFLAGS_FOR_BUILD CXX
-  ../gcc-%{gcc_version}/configure \
+
+  ../${source_dir_0}/configure \
     --prefix=%{_prefix} \
     --bindir=%{_bindir} \
     --exec_prefix=%{_exec_prefix} \
@@ -147,18 +177,18 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
     %{?enable_obsolete:--enable-obsolete} \
     --enable-languages="$languages"
 
-  unset CFLAGS CFLAGS_FOR_BUILD CC CXXFLAGS_FOR_BUILD CXX
-
   if test "%_host" != "%_build" ; then
     # Bug in gcc-3.2.1:
     # Somehow, gcc doesn't get syslimits.h right for Cdn-Xs
     mkdir -p gcc/include
-    cp ../gcc-%{gcc_version}/gcc/gsyslimits.h gcc/include/syslimits.h
+    cp ../${source_dir_0}/gcc/gsyslimits.h gcc/include/syslimits.h
   fi
 
   %{__make} %{?_smp_mflags} all
   cd ..
 
+  unset CFLAGS CFLAGS_FOR_BUILD CC CXXFLAGS_FOR_BUILD CXX
+
 %install
   %{__rmdir} $SB_BUILD_ROOT
 
@@ -179,6 +209,12 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   # Don't want libffi's man-pages
   %{__rmfile} $SB_BUILD_ROOT%{_mandir}/man3/*ffi*
 
+  # Clean the symlinks away incase the source is a repo
+  %{__rmfile} ${source_dir_0}/newlib
+  %{__rmfile} ${source_dir_0}/mpfr
+  %{__rmfile} ${source_dir_0}/mpc
+  %{__rmfile} ${source_dir_0}/gmp
+
 %testing
   # Add testing here.
   export RUNTESTFLAGS=--target_board=%{_target}-run
diff --git a/source-builder/sb/build.py b/source-builder/sb/build.py
index 1e772a6..f82dd99 100644
--- a/source-builder/sb/build.py
+++ b/source-builder/sb/build.py
@@ -1,6 +1,6 @@
 #
 # RTEMS Tools Project (http://www.rtems.org/)
-# Copyright 2010-2012 Chris Johns (chrisj@rtems.org)
+# Copyright 2010-2013 Chris Johns (chrisj@rtems.org)
 # All rights reserved.
 #
 # This file is part of the RTEMS Tools package in 'rtems-tools'.
@@ -34,6 +34,7 @@ import urlparse
 try:
     import check
     import config
+    import download
     import error
     import execute
     import log
@@ -125,115 +126,6 @@ class build:
         if not self.opts.dry_run():
             path.mkdir(mkpath)
 
-    def get_file(self, url, local):
-        if local is None:
-            raise error.general('source/patch path invalid')
-        if not path.isdir(path.dirname(local)) and not self.opts.download_disabled():
-            _notice(self.opts,
-                    'Creating source directory: %s' % (os.path.relpath(path.host(path.dirname(local)))))
-            self.mkdir(path.host(path.dirname(local)))
-        if not path.exists(local):
-            if self.opts.download_disabled():
-                raise error.general('source not found: %s' % (path.host(local)))
-            #
-            # Not localy found so we need to download it. Check if a URL has
-            # been provided on the command line.
-            #
-            url_bases = self.opts.urls()
-            urls = []
-            if url_bases is not None:
-                for base in url_bases:
-                    if base[-1:] != '/':
-                        base += '/'
-                    url_path = urlparse.urlsplit(url)[2]
-                    slash = url_path.rfind('/')
-                    if slash < 0:
-                        url_file = url_path
-                    else:
-                        url_file = url_path[slash + 1:]
-                    urls.append(urlparse.urljoin(base, url_file))
-            urls.append(url)
-            if self.opts.trace():
-                print '_url:', ','.join(urls), '->', local
-            for url in urls:
-                #
-                # Hack for GitHub.
-                #
-                if url.startswith('https://api.github.com'):
-                    url = urlparse.urljoin(url, self.config.expand('tarball/%{version}'))
-                _notice(self.opts, 'download: %s -> %s' % (url, os.path.relpath(path.host(local))))
-                if not self.opts.dry_run():
-                    failed = False
-                    _in = None
-                    _out = None
-                    try:
-                        _in = urllib2.urlopen(url)
-                        _out = open(path.host(local), 'wb')
-                        _out.write(_in.read())
-                    except IOError, err:
-                        msg = 'download: %s: error: %s' % (url, str(err))
-                        _notice(self.opts, msg)
-                        if path.exists(local):
-                            os.remove(path.host(local))
-                        failed = True
-                    except ValueError, err:
-                        msg = 'download: %s: error: %s' % (url, str(err))
-                        _notice(self.opts, msg)
-                        if path.exists(local):
-                            os.remove(path.host(local))
-                        failed = True
-                    except:
-                        msg = 'download: %s: error' % (url)
-                        print >> sys.stderr, msg
-                        if _out is not None:
-                            _out.close()
-                        raise
-                    if _out is not None:
-                        _out.close()
-                    if _in is not None:
-                        del _in
-                    if not failed:
-                        if not path.isfile(local):
-                            raise error.general('source is not a file: %s' % (path.host(local)))
-                        return
-            if not self.opts.dry_run():
-                raise error.general('downloading %s: all paths have failed, giving up' % (url))
-
-    def parse_url(self, url, pathkey):
-        #
-        # Split the source up into the parts we need.
-        #
-        source = {}
-        source['url'] = url
-        source['path'] = path.dirname(url)
-        source['file'] = path.basename(url)
-        source['name'], source['ext'] = path.splitext(source['file'])
-        #
-        # Get the file. Checks the local source directory first.
-        #
-        source['local'] = None
-        for p in self.config.define(pathkey).split(':'):
-            local = path.join(path.abspath(p), source['file'])
-            if source['local'] is None:
-                source['local'] = local
-            if path.exists(local):
-                source['local'] = local
-                break
-        #
-        # Is the file compressed ?
-        #
-        esl = source['ext'].split('.')
-        if esl[-1:][0] == 'gz':
-            source['compressed'] = '%{__gzip} -dc'
-        elif esl[-1:][0] == 'bz2':
-            source['compressed'] = '%{__bzip2} -dc'
-        elif esl[-1:][0] == 'bz2':
-            source['compressed'] = '%{__zip} -u'
-        elif esl[-1:][0] == 'xz':
-            source['compressed'] = '%{__xz} -dc'
-        source['script'] = ''
-        return source
-
     def source(self, package, source_tag):
         #
         # Scan the sources found in the config file for the one we are
@@ -250,9 +142,11 @@ class build:
                     break
         if url is None:
             raise error.general('source tag not found: source%d' % (source_tag))
-        source = self.parse_url(url, '_sourcedir')
-        self.get_file(source['url'], source['local'])
-        if 'compressed' in source:
+        source = download.parse_url(url, '_sourcedir', self.config, self.opts)
+        download.get_file(source['url'], source['local'], self.opts, self.config)
+        if 'symlink' in source:
+            source['script'] = '%%{__ln_s} %s ${source_dir_%d}' % (source['local'], source_tag)
+        elif 'compressed' in source:
             source['script'] = source['compressed'] + ' ' + \
                 source['local'] + ' | %{__tar_extract} -'
         else:
@@ -275,13 +169,13 @@ class build:
         #
         # Parse the URL first in the source builder's patch directory.
         #
-        patch = self.parse_url(url, '_patchdir')
+        patch = download.parse_url(url, '_patchdir', self.config, self.opts)
         #
         # If not in the source builder package check the source directory.
         #
         if not path.exists(patch['local']):
-            patch = self.parse_url(url, '_patchdir')
-        self.get_file(patch['url'], patch['local'])
+            patch = download.parse_url(url, '_patchdir', self.config, self.opts)
+        download.get_file(patch['url'], patch['local'], self.opts, self.config)
         if 'compressed' in patch:
             patch['script'] = patch['compressed'] + ' ' +  patch['local']
         else:
diff --git a/source-builder/sb/download.py b/source-builder/sb/download.py
new file mode 100644
index 0000000..8b6be2c
--- /dev/null
+++ b/source-builder/sb/download.py
@@ -0,0 +1,237 @@
+#
+# RTEMS Tools Project (http://www.rtems.org/)
+# Copyright 2010-2013 Chris Johns (chrisj@rtems.org)
+# All rights reserved.
+#
+# This file is part of the RTEMS Tools package in 'rtems-tools'.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#
+# This code builds a package given a config file. It only builds to be
+# installed not to be package unless you run a packager around this.
+#
+
+import os
+import stat
+import sys
+import urllib2
+import urlparse
+
+import error
+import git
+import log
+import path
+
+def _notice(opts, text):
+    if not opts.quiet() and not log.default.has_stdout():
+        print text
+    log.output(text)
+    log.flush()
+
+def _output(opts, text):
+    if not opts.quiet():
+        log.output(text)
+
+def _http_parser(source, config, opts):
+    #
+    # Is the file compressed ?
+    #
+    esl = source['ext'].split('.')
+    if esl[-1:][0] == 'gz':
+        source['compressed'] = '%{__gzip} -dc'
+    elif esl[-1:][0] == 'bz2':
+        source['compressed'] = '%{__bzip2} -dc'
+    elif esl[-1:][0] == 'bz2':
+        source['compressed'] = '%{__zip} -u'
+    elif esl[-1:][0] == 'xz':
+        source['compressed'] = '%{__xz} -dc'
+
+def _git_parser(source, config, opts):
+    #
+    # Symlink.
+    #
+    us = source['url'].split('?')
+    source['path'] = path.dirname(us[0])
+    source['file'] = path.basename(us[0])
+    source['name'], source['ext'] = path.splitext(source['file'])
+    if len(us) > 1:
+        source['args'] = us[1:]
+    source['local'] = \
+        path.join(source['local_prefix'], config.expand('git'), source['file'])
+    source['symlink'] = source['local']
+
+
+def _file_parser(source, config, opts):
+    #
+    # Symlink.
+    #
+    source['symlink'] = source['local']
+
+parsers = { 'http': _http_parser,
+            'ftp':  _http_parser,
+            'git':  _git_parser,
+            'file':  _file_parser }
+
+def parse_url(url, pathkey, config, opts):
+    #
+    # Split the source up into the parts we need.
+    #
+    source = {}
+    source['url'] = url
+    source['path'] = path.dirname(url)
+    source['file'] = path.basename(url)
+    source['name'], source['ext'] = path.splitext(source['file'])
+    #
+    # Get the file. Checks the local source directory first.
+    #
+    source['local'] = None
+    for p in config.define(pathkey).split(':'):
+        local = path.join(path.abspath(p), source['file'])
+        if source['local'] is None:
+            source['local_prefix'] = path.abspath(p)
+            source['local'] = local
+        if path.exists(local):
+            source['local_prefix'] = path.abspath(p)
+            source['local'] = local
+            break
+    source['script'] = ''
+    for p in parsers:
+        if url.startswith(p):
+            source['type'] = p
+            if parsers[p](source, config, opts):
+                break
+    return source
+
+def _http_downloader(url, local, config, opts):
+    if path.exists(local):
+        return True
+    #
+    # Hack for GitHub.
+    #
+    if url.startswith('https://api.github.com'):
+        url = urlparse.urljoin(url, config.expand('tarball/%{version}'))
+    _notice(opts, 'download: %s -> %s' % (url, os.path.relpath(path.host(local))))
+    failed = False
+    if not opts.dry_run():
+        _in = None
+        _out = None
+        try:
+            _in = urllib2.urlopen(url)
+            _out = open(path.host(local), 'wb')
+            _out.write(_in.read())
+        except IOError, err:
+            msg = 'download: %s: error: %s' % (url, str(err))
+            _notice(opts, msg)
+            if path.exists(local):
+                os.remove(path.host(local))
+            failed = True
+        except ValueError, err:
+            msg = 'download: %s: error: %s' % (url, str(err))
+            _notice(opts, msg)
+            if path.exists(local):
+                os.remove(path.host(local))
+            failed = True
+        except:
+            msg = 'download: %s: error' % (url)
+            print >> sys.stderr, msg
+            if _out is not None:
+                _out.close()
+            raise
+        if _out is not None:
+            _out.close()
+        if _in is not None:
+            del _in
+        if not failed:
+            if not path.isfile(local):
+                raise error.general('source is not a file: %s' % (path.host(local)))
+    return not failed
+
+def _git_downloader(url, local, config, opts):
+    rlp = os.path.relpath(path.host(local))
+    us = url.split('?')
+    repo = git.repo(local, opts, config.macros)
+    if not repo.valid():
+        _notice(opts, 'git: clone: %s -> %s' % (us[0], rlp))
+        if not opts.dry_run():
+            repo.clone(us[0], local)
+    for a in us[1:]:
+        _as = a.split('=')
+        if _as[0] == 'branch':
+            _notice(opts, 'git: checkout: %s => %s' % (us[0], _as[1]))
+            if not opts.dry_run():
+                repo.checkout(_as[1])
+        elif _as[0] == 'pull':
+            _notice(opts, 'git: pull: %s' % (us[0]))
+            if not opts.dry_run():
+                repo.pull()
+        elif _as[0] == 'fetch':
+            _notice(opts, 'git: fetch: %s -> %s' % (us[0], rlp))
+            if not opts.dry_run():
+                repo.fetch()
+        elif _as[0] == 'reset':
+            arg = []
+            if len(_as) > 1:
+                arg = ['--%s' % (_as[1])]
+            _notice(opts, 'git: reset: %s' % (us[0]))
+            if not opts.dry_run():
+                repo.reset(arg)
+    return True
+
+def _file_downloader(url, local, config, opts):
+    if path.exists(local):
+        return True
+    return path.isdir(url)
+
+downloaders = { 'http': _http_downloader,
+                'ftp':  _http_downloader,
+                'git':  _git_downloader,
+                'file':  _file_downloader }
+
+def get_file(url, local, opts, config):
+    if local is None:
+        raise error.general('source/patch path invalid')
+    if not path.isdir(path.dirname(local)) and not opts.download_disabled():
+        _notice(opts,
+                'Creating source directory: %s' % (os.path.relpath(path.host(path.dirname(local)))))
+    _output(opts, 'making dir: %s' % (path.host(path.dirname(local))))
+    if not opts.dry_run():
+        path.mkdir(path.dirname(local))
+    if not path.exists(local) and opts.download_disabled():
+        raise error.general('source not found: %s' % (path.host(local)))
+    #
+    # Check if a URL hasbeen provided on the command line.
+    #
+    url_bases = opts.urls()
+    urls = []
+    if url_bases is not None:
+        for base in url_bases:
+            if base[-1:] != '/':
+                base += '/'
+            url_path = urlparse.urlsplit(url)[2]
+            slash = url_path.rfind('/')
+            if slash < 0:
+                url_file = url_path
+            else:
+                url_file = url_path[slash + 1:]
+            urls.append(urlparse.urljoin(base, url_file))
+    urls.append(url)
+    if opts.trace():
+        print '_url:', ','.join(urls), '->', local
+    for url in urls:
+        for dl in downloaders:
+            if url.startswith(dl):
+                if downloaders[dl](url, local, config, opts):
+                    return
+    if not opts.dry_run():
+        raise error.general('downloading %s: all paths have failed, giving up' % (url))
diff --git a/source-builder/sb/git.py b/source-builder/sb/git.py
index 1b84484..5d1531a 100644
--- a/source-builder/sb/git.py
+++ b/source-builder/sb/git.py
@@ -37,7 +37,11 @@ class repo:
 
     def _run(self, args, check = False):
         e = execute.capture_execution()
-        exit_code, proc, output = e.spawn([self.git] + args)
+        if path.exists(self.path):
+            cwd = self.path
+        else:
+            cwd = None
+        exit_code, proc, output = e.spawn([self.git] + args, cwd = cwd)
         if check:
             self._git_exit_code(exit_code)
         return exit_code, output
@@ -61,28 +65,63 @@ class repo:
             raise error.general('invalid version number from git: %s' % (gvs[2]))
         return (int(vs[0]), int(vs[1]), int(vs[2]), int(vs[3]))
 
+    def clone(self, url, path):
+        ec, output = self._run(['clone', url, path])
+        if ec != 0:
+            raise error.general('clone of %s failed: %s' % (url, output))
+
+    def fetch(self, url, path):
+        ec, output = self._run(['fetch', url])
+        if ec != 0:
+            raise error.general('fetch of %s failed: %s' % (url, output))
+
+    def pull(self):
+        ec, output = self._run(['pull'])
+        if ec != 0:
+            raise error.general('pull of %s failed: %s' % (url, output))
+
+    def reset(self, args):
+        if type(args) == str:
+            args = [args]
+        ec, output = self._run(['reset'] + args)
+        if ec != 0:
+            raise error.general('pull of %s failed: %s' % (url, output))
+
+    def branch(self):
+        ec, output = self._run(['branch'])
+        if ec == 0:
+            for b in output.split('\n'):
+                if b[0] == '*':
+                    return b[2:]
+        return None
+
+    def checkout(self, branch = 'master'):
+        ec, output = self._run(['checkout', branch])
+        return ec == 0
+
     def status(self):
         _status = {}
-        ec, output = self._run(['status'])
-        if ec == 0:
-            state = 'none'
-            for l in output.split('\n'):
-                if l.startswith('# On branch '):
-                    _status['branch'] = l[len('# On branch '):]
-                elif l.startswith('# Changes to be committed:'):
-                    state = 'staged'
-                elif l.startswith('# Changes not staged for commit:'):
-                    state = 'unstaged'
-                elif l.startswith('# Untracked files:'):
-                    state = 'untracked'
-                elif state != 'none' and l[0] == '#':
-                    if l.strip() != '#' and not l.startswith('#   ('):
-                        if state not in _status:
-                            _status[state] = []
-                        l = l[1:]
-                        if ':' in l:
-                            l = l.split(':')[1]
-                        _status[state] += [l.strip()]
+        if path.exists(self.path):
+            ec, output = self._run(['status'])
+            if ec == 0:
+                state = 'none'
+                for l in output.split('\n'):
+                    if l.startswith('# On branch '):
+                        _status['branch'] = l[len('# On branch '):]
+                    elif l.startswith('# Changes to be committed:'):
+                        state = 'staged'
+                    elif l.startswith('# Changes not staged for commit:'):
+                        state = 'unstaged'
+                    elif l.startswith('# Untracked files:'):
+                        state = 'untracked'
+                    elif state != 'none' and l[0] == '#':
+                        if l.strip() != '#' and not l.startswith('#   ('):
+                            if state not in _status:
+                                _status[state] = []
+                            l = l[1:]
+                            if ':' in l:
+                                l = l.split(':')[1]
+                            _status[state] += [l.strip()]
         return _status
 
     def clean(self):
@@ -90,8 +129,10 @@ class repo:
         return len(_status) == 1 and 'branch' in _status
 
     def valid(self):
-        ec, output = self._run(['status'])
-        return ec == 0
+        if path.exists(self.path):
+            ec, output = self._run(['status'])
+            return ec == 0
+        return False
 
     def remotes(self):
         _remotes = {}