contrib/dockerlib.sh

match: introduce boolean prefix() method

tl;dr: This is another step towards a (previously unstated) goal of
eliminating match.files() in conditions.

There are four types of matchers:

 * always: Matches everything, checked with always(), files() is empty

 * exact: Matches exact set of files, checked with isexact(), files()
   contains the files to match

 * patterns: Matches more complex patterns, checked with anypats(),
   files() contains roots of the matched patterns

 * prefix: Matches simple 'path:' patterns as prefixes ('foo' matches
   both 'foo' and 'foo/bar'), no single method to check, files()
   contains the prefixes to match

For completeness, it would be nice to have a method for checking for
the "prefix" type of matcher as well, so let's add that, making it
return True simply when none of the others do.

The larger goal here is to eliminate uses of match.files() in
conditions (i.e. bool(match.files())). The reason for this is that
there are scenarios when you would like to create a "prefix" matcher
that happens to match no files. One example is for 'hg files -I foo
bar'. The narrowmatcher also restricts the set of files given and it
would not surprise me if have bugs caused by that already. Note that
'if m.files() and not m.anypats()' and similar is sometimes used to
catch the "exact" and "prefix" cases above.

#!/bin/sh -eu

# This function exists to set up the DOCKER variable and verify that
# it's the binary we expect. It also verifies that the docker service
# is running on the system and we can talk to it.
function checkdocker() {
  if which docker.io >> /dev/null 2>&1 ; then
    DOCKER=docker.io
  elif which docker >> /dev/null 2>&1 ; then
    DOCKER=docker
  else
    echo "Error: docker must be installed"
    exit 1
  fi

  $DOCKER -h 2> /dev/null | grep -q Jansens && { echo "Error: $DOCKER is the Docking System Tray - install docker.io instead"; exit 1; }
  $DOCKER version | grep -q "^Client version:" || { echo "Error: unexpected output from \"$DOCKER version\""; exit 1; }
  $DOCKER version | grep -q "^Server version:" || { echo "Error: could not get docker server version - check it is running and your permissions"; exit 1; }
}

# Construct a container and leave its name in $CONTAINER for future use.
function initcontainer() {
  [ "$1" ] || { echo "Error: platform name must be specified"; exit 1; }

  DFILE="$ROOTDIR/contrib/docker/$1"
  [ -f "$DFILE" ] || { echo "Error: docker file $DFILE not found"; exit 1; }

  CONTAINER="hg-dockerrpm-$1"
  DBUILDUSER=build
  (
    cat $DFILE
    if [ $(uname) = "Darwin" ] ; then
        # The builder is using boot2docker on OS X, so we're going to
        # *guess* the uid of the user inside the VM that is actually
        # running docker. This is *very likely* to fail at some point.
        echo RUN useradd $DBUILDUSER -u 1000
    else
        echo RUN groupadd $DBUILDUSER -g `id -g`
        echo RUN useradd $DBUILDUSER -u `id -u` -g $DBUILDUSER
    fi
  ) | $DOCKER build --tag $CONTAINER -
}