Allow bootstrap to be run before anything else is installed

python/mach_bootstrap.py

@@ -224,11 +224,29 @@ def _is_windows():
     return sys.platform == 'win32'
 
 
+class DummyContext(object):
+    pass
+
+
+def bootstrap_command_only(topdir):
+    from servo.bootstrap import bootstrap
+
+    context = DummyContext()
+    context.topdir = topdir
+    force = False
+    if len(sys.argv) == 3 and sys.argv[2] == "-f":
+        force = True
+    bootstrap(context, force)
+    return 0
+
+
 def bootstrap(topdir):
     _ensure_case_insensitive_if_windows()
 
     topdir = os.path.abspath(topdir)
 
+    len(sys.argv) > 1 and sys.argv[1] == "bootstrap"
+
     # We don't support paths with Unicode characters for now
     # https://github.com/servo/servo/issues/10002
     try:

python/servo/bootstrap.py

@@ -49,11 +49,16 @@ def install_linux_deps(context, pkgs_ubuntu, pkgs_fedora, force):
             command.append('-y')
         print("Installing missing dependencies...")
         run_as_root(command + pkgs)
+        return True
+    return False
+
 
 def install_salt_dependencies(context, force):
     pkgs_apt = ['build-essential', 'libssl-dev', 'libffi-dev', 'python-dev']
     pkgs_dnf = ['gcc', 'libffi-devel', 'python-devel', 'openssl-devel']
-    install_linux_deps(context, pkgs_apt, pkgs_dnf, force)
+    if not install_linux_deps(context, pkgs_apt, pkgs_dnf, force):
+        print("Dependencies are already installed")
+
 
 def gstreamer(context, force=False):
     cur = os.curdir
@@ -62,6 +67,9 @@ def gstreamer(context, force=False):
         os.chdir(gstdir)
         subprocess.call(["bash", "gstreamer.sh"])
         os.chdir(cur)
+        return True
+    return False
+
 
 def linux(context, force=False):
     # Please keep these in sync with the packages in README.md
@@ -98,11 +106,13 @@ def linux(context, force=False):
     else:
         pkgs_apt += ["libssl1.0-dev"]
 
-    install_linux_deps(context, pkgs_apt, pkgs_dnf, force)
+    installed_something = install_linux_deps(context, pkgs_apt, pkgs_dnf, force)
 
     if not check_gstreamer_lib():
-        gstreamer(context, force)
+        installed_something |= gstreamer(context, force)
 
+    if not installed_something:
+        print("Dependencies were already installed!")
 
 
 def salt(context, force=False):

python/servo/util.py

@@ -20,7 +20,6 @@ import StringIO
 import sys
 import zipfile
 import urllib2
-import certifi
 
 
 try:
@@ -30,6 +29,7 @@ except ImportError:
 
 # The cafile parameter was added in 2.7.9
 if HAS_SNI and sys.version_info >= (2, 7, 9):
+    import certifi
     STATIC_RUST_LANG_ORG_DIST = "https://static.rust-lang.org/dist"
     URLOPEN_KWARGS = {"cafile": certifi.where()}
 else: