Add providing location for fetch_via_{vcs,git}

This allows to call fetch_via_{vcs,git} multiple times for a location to
have another revision.

Example:
fetch_via_git("git+https://github.com/nexB/fetchcode.git", location="/tmp/repo")
will checkout tip of default branch
fetch_via_git("git+https://github.com/nexB/fetchcode.git@ccb7b6199681910ccf047f1a18aa89ece45d665c",
     location="/home/amazuruk/dupa/master")
will reset to ccb7b61

Additionally remove some trailing whitespaces and fix indentation of a
docstring.

Signed-off-by: Alexander Mazuruk <a.mazuruk@samsung.com>

src/fetchcode/__init__.py

@@ -41,7 +41,7 @@ def __init__(self, location, content_type, size, url):
 def fetch_http(url, location):
     """
     Return a `Response` object built from fetching the content at a HTTP/HTTPS based `url` URL string
-    saving the content in a file at `location`   
+    saving the content in a file at `location`
     """
     r = requests.get(url)
     with open(location, 'wb') as f:
@@ -59,7 +59,7 @@ def fetch_http(url, location):
 def fetch_ftp(url, location):
     """
     Return a `Response` object built from fetching the content at a FTP based `url` URL string
-    saving the content in a file at `location`  
+    saving the content in a file at `location`
     """
     url_parts = urlparse(url)
 

src/fetchcode/vcs/__init__.py

@@ -29,9 +29,9 @@
 class VCSResponse:
     """
     Represent the response from fetching a VCS URL with:
-- `dest_dir`: destination of directory
-- `vcs_type`: VCS Type of URL (git,bzr,hg,svn)
-- `domain` : Source of git VCS (GitHub, Gitlab, Bitbucket)
+    - `dest_dir`: destination of directory
+    - `vcs_type`: VCS Type of URL (git,bzr,hg,svn)
+    - `domain` : Source of git VCS (GitHub, Gitlab, Bitbucket)
     """
 
     def __init__(self, dest_dir, vcs_type, domain):
@@ -40,16 +40,17 @@ def __init__(self, dest_dir, vcs_type, domain):
         self.domain = domain
 
 
-def fetch_via_vcs(url):
+def fetch_via_vcs(url, location=None):
     """
     Take `url` as input and store the content of it at location specified at `location` string
-    Return a VCSResponse object 
+    Return a VCSResponse object
     """
     parsed_url = urlparse(url)
     scheme = parsed_url.scheme
     domain = parsed_url.netloc
-    temp = tempfile.mkdtemp()
-    os.rmdir(temp)
+    if location is None:
+        location = tempfile.mkdtemp()
+        os.rmdir(location)
     if scheme not in vcs.all_schemes:
         raise Exception("Not a supported/known scheme.")
 
@@ -58,6 +59,6 @@ def fetch_via_vcs(url):
             vcs_type = vcs_name
 
     backend = vcs.get_backend_for_scheme(scheme)
-    backend.obtain(dest=temp, url=misc.hide_url(url))
+    backend.obtain(dest=location, url=misc.hide_url(url))
 
-    return VCSResponse(dest_dir=temp, vcs_type=vcs_type, domain=domain)
+    return VCSResponse(dest_dir=location, vcs_type=vcs_type, domain=domain)

src/fetchcode/vcs/git.py

@@ -19,21 +19,28 @@
 from urllib.parse import urlparse
 
 from fetchcode.vcs.pip._internal.vcs.git import Git
+from fetchcode.vcs.pip._internal.vcs.versioncontrol import RevOptions
 from fetchcode.vcs.pip._internal.utils import misc
 from fetchcode.vcs.pip._internal.vcs import vcs
 from fetchcode.vcs import VCSResponse
 
 
-def fetch_via_git(url):
+def fetch_via_git(url, location=None):
+    """
+    Take `url` as input and store the content of it at location specified at `location` string
+    If location string is not set, a tempfile.mkdtemp() will be created to store content in.
+    tempfile.mkdtemp must be cleaned by user manually.
+    Return a VCSResponse object
+    """
     parsed_url = urlparse(url)
     scheme = parsed_url.scheme
     domain = parsed_url.netloc
-    temp = tempfile.mkdtemp()
-    os.rmdir(temp)
+    if location is None:
+        location = tempfile.mkdtemp()
+        os.rmdir(location)
     if scheme not in Git.schemes:
         raise Exception("Not a Git based scheme.")
 
     backend = vcs.get_backend(name="git")
-    backend.obtain(dest=temp, url=misc.hide_url(url))
-
-    return VCSResponse(dest_dir=temp, vcs_type="git", domain=domain)
+    backend.obtain(dest=location, url=misc.hide_url(url))
+    return VCSResponse(dest_dir=location, vcs_type="git", domain=domain)