Add vercmp function

The existing vercmp_numbers function only handles, as the name says,
numbers.  I noticed that "sort" has had a version sort for a long time
[1] and, rather than re-implement it badly, use this as a version of
vercmp that works a bit more naturally.

This is intended to be used in an "if" statement as in

  prog_ver=$(prog_ver --version | grep ...)
  if vercmp $prog_ver "<" 2.0; then
     ...
  fi

A test-case is added to test the basic features and some edge-cases.

[1] http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=4c9fae4e97d95a9f89d1399a8aeb03051f0fec96

Change-Id: Ie55283acdc40a095b80b2631a55310072883ad0d

functions

@@ -527,12 +527,58 @@ function vercmp_numbers {
     typeset v1=$1 v2=$2 sep
     typeset -a ver1 ver2
 
+    deprecated "vercmp_numbers is deprecated for more generic vercmp"
+
     IFS=. read -ra ver1 <<< "$v1"
     IFS=. read -ra ver2 <<< "$v2"
 
     _vercmp_r "${#ver1[@]}" "${ver1[@]}" "${ver2[@]}"
 }
 
+# vercmp ver1 op ver2
+#  Compare VER1 to VER2
+#   - op is one of < <= == >= >
+#   - returns true if satisified
+#  e.g.
+#  if vercmp 1.0 "<" 2.0; then
+#    ...
+#  fi
+function vercmp {
+    local v1=$1
+    local op=$2
+    local v2=$3
+    local result
+
+    # sort the two numbers with sort's "-V" argument.  Based on if v2
+    # swapped places with v1, we can determine ordering.
+    result=$(echo -e "$v1\n$v2" | sort -V | head -1)
+
+    case $op in
+        "==")
+            [ "$v1" = "$v2" ]
+            return
+            ;;
+        ">")
+            [ "$v1" != "$v2" ] && [ "$result" = "$v2" ]
+            return
+            ;;
+        "<")
+            [ "$v1" != "$v2" ] && [ "$result" = "$v1" ]
+            return
+            ;;
+        ">=")
+            [ "$result" = "$v2" ]
+            return
+            ;;
+        "<=")
+            [ "$result" = "$v1" ]
+            return
+            ;;
+        *)
+            die $LINENO "unrecognised op: $op"
+            ;;
+    esac
+}
 
 # This function sets log formatting options for colorizing log
 # output to stdout. It is meant to be called by lib modules.

tests/test_vercmp.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+
+# Tests for DevStack vercmp functionality
+
+TOP=$(cd $(dirname "$0")/.. && pwd)
+
+# Import common functions
+source $TOP/functions
+source $TOP/tests/unittest.sh
+
+assert_true "numeric gt"  vercmp 2.0 ">" 1.0
+assert_true "numeric gte" vercmp 2.0 ">=" 1.0
+assert_true "numeric gt"  vercmp 1.0.1 ">" 1.0
+assert_true "numeric gte" vercmp 1.0.1 ">=" 1.0
+assert_true "alpha gt"    vercmp 1.0.1b ">" 1.0.1a
+assert_true "alpha gte"   vercmp 1.0.1b ">=" 1.0.1a
+assert_true "alpha gt"    vercmp b ">" a
+assert_true "alpha gte"   vercmp b ">=" a
+assert_true "alpha gt"    vercmp 2.0-rc3 ">" 2.0-rc1
+assert_true "alpha gte"   vercmp 2.0-rc3 ">=" 2.0-rc1
+
+assert_false "numeric gt fail"  vercmp 1.0 ">" 1.0
+assert_true  "numeric gte"      vercmp 1.0 ">=" 1.0
+assert_false "numeric gt fail"  vercmp 0.9 ">" 1.0
+assert_false "numeric gte fail" vercmp 0.9 ">=" 1.0
+assert_false "numeric gt fail"  vercmp 0.9.9 ">" 1.0
+assert_false "numeric gte fail" vercmp 0.9.9 ">=" 1.0
+assert_false "numeric gt fail"  vercmp 0.9a.9 ">" 1.0.1
+assert_false "numeric gte fail" vercmp 0.9a.9 ">=" 1.0.1
+
+assert_false "numeric lt"  vercmp 1.0 "<" 1.0
+assert_true  "numeric lte" vercmp 1.0 "<=" 1.0
+assert_true "numeric lt"   vercmp 1.0 "<" 1.0.1
+assert_true "numeric lte"  vercmp 1.0 "<=" 1.0.1
+assert_true "alpha lt"     vercmp 1.0.1a "<" 1.0.1b
+assert_true "alpha lte"    vercmp 1.0.1a "<=" 1.0.1b
+assert_true "alpha lt"     vercmp a "<" b
+assert_true "alpha lte"    vercmp a "<=" b
+assert_true "alpha lt"     vercmp 2.0-rc1 "<" 2.0-rc3
+assert_true "alpha lte"    vercmp 2.0-rc1 "<=" 2.0-rc3
+
+assert_true "eq"       vercmp 1.0 "==" 1.0
+assert_true "eq"       vercmp 1.0.1 "==" 1.0.1
+assert_false "eq fail" vercmp 1.0.1 "==" 1.0.2
+assert_false "eq fail" vercmp 2.0-rc1 "==" 2.0-rc2
+
+report_results

tests/unittest.sh

@@ -92,6 +92,51 @@ function assert_empty {
     fi
 }
 
+# assert the arguments evaluate to true
+#  assert_true "message" arg1 arg2
+function assert_true {
+    local lineno
+    lineno=`caller 0 | awk '{print $1}'`
+    local function
+    function=`caller 0 | awk '{print $2}'`
+    local msg=$1
+    shift
+
+    $@
+    if [ $? -eq 0 ]; then
+        PASS=$((PASS+1))
+        echo "PASS: $function:L$lineno - $msg"
+    else
+        FAILED_FUNCS+="$function:L$lineno\n"
+        echo "ERROR: test failed in $function:L$lineno!"
+        echo "  $msg"
+        ERROR=$((ERROR+1))
+    fi
+}
+
+# assert the arguments evaluate to false
+#  assert_false "message" arg1 arg2
+function assert_false {
+    local lineno
+    lineno=`caller 0 | awk '{print $1}'`
+    local function
+    function=`caller 0 | awk '{print $2}'`
+    local msg=$1
+    shift
+
+    $@
+    if [ $? -eq 0 ]; then
+        FAILED_FUNCS+="$function:L$lineno\n"
+        echo "ERROR: test failed in $function:L$lineno!"
+        echo "  $msg"
+        ERROR=$((ERROR+1))
+    else
+        PASS=$((PASS+1))
+        echo "PASS: $function:L$lineno - $msg"
+    fi
+}
+
+
 # Print a summary of passing and failing tests and exit
 # (with an error if we have failed tests)
 #  usage: report_results