#!/bin/bash
#
# Run in the top of the source directory which must be a git repo, on a branch
# other than master so that we can find C files that are different from
# master.
#
# Installed binaries configured with --enable-coverage must be in PATH..

set -e

# you probably want just "gcov", but I currently have loads of versions of GCC installed...
GCOV=gcov-mp-6
SQL_FILES="partition_join.sql partition_join_extras.sql"
TMP=tmp
export PAGER=

# Set up workspace and cluster.
mkdir -p $TMP
mkdir -p $TMP/sql
mkdir -p $TMP/gcov
mkdir -p $TMP/results
rm -fr $TMP/pgdata
initdb -D $TMP/pgdata

for sql_file in $SQL_FILES ; do
  # Consider each file as a set of blocks separated by blank lines or lines
  # made from - and = characters.  Number all blocks that contain SELECT or
  # PREPARE in a SQL comment.
  awk '
BEGIN {
  blockno = 0;
  numbered_buffer = "";
  plain_buffer = "";
  interesting = 0;
}

/^[\-= ]*$/ {
  if (interesting) {
    printf("%s", numbered_buffer);
    blockno++;
  } else {
    printf("%s", plain_buffer);
  }
  interesting = 0;
  numbered_buffer = "";
  plain_buffer = "";
  print;
  next;
}

{
  if ($0 ~ /^(select|SELECT|prepare|PREPARE)/ ) {
    interesting = 1;
  }
  numbered_buffer = numbered_buffer sprintf("/*BLOCK%s*/ %s\n", blockno, $0);
  plain_buffer = plain_buffer sprintf("%s\n", $0);
}' < src/test/regress/sql/$sql_file > $TMP/sql/$sql_file

  # Find the highest block number.
  highest_blockno=$(sed -n 's|^/\*BLOCK\([0-9]*\)\*/.*$|\1|p' < $TMP/sql/$sql_file | tail -1)

  # For each block number, produce a version of the file with all numbered
  # blocks but that one commented out.
  for blockno in $(seq 0 $highest_blockno) ; do
    awk "
    /^\/\*BLOCK$blockno\*\// {
      print;
      next;
    }
    /^\/\*BLOCK[0-9]*\*\// {
      printf(\"-- %s\n\", \$0);
      next;
    }
    { print; }
    " < $TMP/sql/$sql_file > $TMP/sql/$sql_file.$blockno
  done

  # Run all the variants...
  for blockno in $(seq 0 $highest_blockno) ; do
    find . -name '*.gcda' -print | xargs rm
    pg_ctl -w -D $TMP/pgdata start
    psql postgres -c 'DROP SCHEMA IF EXISTS pwj_extra CASCADE; DROP SCHEMA IF EXISTS public CASCADE; CREATE SCHEMA public'
    psql postgres -f $TMP/sql/$sql_file.$blockno
    pg_ctl -w -D $TMP/pgdata stop
    for c_file in $( git diff master... --stat --name-only | grep \.c\$ ) ; do
      echo $c_file
      ( cd $(dirname $c_file) && $GCOV $(basename $c_file) )
      cp $c_file.gcov $TMP/gcov/$(basename $c_file).$sql_file.$blockno.gcov
    done
  done
done

# Merge all of this information into unreadable output file showing which
# blocks of SQL hit which lines of C.
for c_file in $( git diff master... --stat --name-only | grep \.c\$ ) ; do
  output=$TMP/results/$(basename $c_file).aggregated_coverage
  sed 's/$/    SQL blocks:/' < $c_file > $output
  codes=ABCDEFG
  for sql_file in $SQL_FILES ; do
    code=$(echo $codes | cut -c1)
    codes=$(echo $codes | cut -c2-)
    highest_blockno=$(sed -n 's|^/\*BLOCK\([0-9]*\)\*/.*$|\1|p' < $TMP/sql/$sql_file | tail -1)

    for blockno in $(seq 0 $highest_blockno) ; do
      grep -vE '^ *-: *0:' $TMP/gcov/$(basename $c_file).$sql_file.$blockno.gcov | sed "s/^ *[0-9][0-9]*:.*$/ $code$blockno/;s/^ [^A-Z].*$//" | paste -d '\0' $output - > $output.tmp
      mv $output.tmp $output
    done
  done
  sed 's/    SQL blocks:$//' < $output > $output.tmp
  mv $output.tmp $output
done