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Merge pull request #275 from tristan0x/require_tool

New script $ZSH/tools/require_tool.sh to ensure version of tool

Robby Russell authored on 10/10/2011 at 12:08:38
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tools/require_tool.sh
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+__require_tool_version_compare ()
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+{
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+  (
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+    # Locally ignore failures, otherwise we'll exit whenever $1 and $2
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+    # are not equal!
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+    set +e
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+
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+awk_strverscmp='
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+  # Use only awk features that work with 7th edition Unix awk (1978).
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+  # My, what an old awk you have, Mr. Solaris!
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+  END {
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+    while (length(v1) || length(v2)) {
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+      # Set d1 to be the next thing to compare from v1, and likewise for d2.
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+      # Normally this is a single character, but if v1 and v2 contain digits,
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+      # compare them as integers and fractions as strverscmp does.
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+      if (v1 ~ /^[0-9]/ && v2 ~ /^[0-9]/) {
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+	# Split v1 and v2 into their leading digit string components d1 and d2,
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+	# and advance v1 and v2 past the leading digit strings.
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+	for (len1 = 1; substr(v1, len1 + 1) ~ /^[0-9]/; len1++) continue
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+	for (len2 = 1; substr(v2, len2 + 1) ~ /^[0-9]/; len2++) continue
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+	d1 = substr(v1, 1, len1); v1 = substr(v1, len1 + 1)
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+	d2 = substr(v2, 1, len2); v2 = substr(v2, len2 + 1)
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+	if (d1 ~ /^0/) {
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+	  if (d2 ~ /^0/) {
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+	    # Compare two fractions.
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+	    while (d1 ~ /^0/ && d2 ~ /^0/) {
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+	      d1 = substr(d1, 2); len1--
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+	      d2 = substr(d2, 2); len2--
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+	    }
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+	    if (len1 != len2 && ! (len1 && len2 && substr(d1, 1, 1) == substr(d2, 1, 1))) {
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+	      # The two components differ in length, and the common prefix
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+	      # contains only leading zeros.  Consider the longer to be less.
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+	      d1 = -len1
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+	      d2 = -len2
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+	    } else {
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+	      # Otherwise, compare as strings.
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+	      d1 = "x" d1
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+	      d2 = "x" d2
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+	    }
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+	  } else {
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+	    # A fraction is less than an integer.
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+	    exit 1
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+	  }
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+	} else {
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+	  if (d2 ~ /^0/) {
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+	    # An integer is greater than a fraction.
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+	    exit 2
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+	  } else {
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+	    # Compare two integers.
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+	    d1 += 0
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+	    d2 += 0
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+	  }
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+	}
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+      } else {
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+	# The normal case, without worrying about digits.
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+	if (v1 == "") d1 = v1; else { d1 = substr(v1, 1, 1); v1 = substr(v1,2) }
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+	if (v2 == "") d2 = v2; else { d2 = substr(v2, 1, 1); v2 = substr(v2,2) }
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+      }
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+      if (d1 < d2) exit 1
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+      if (d1 > d2) exit 2
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+    }
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+  }
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+'
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+    awk "$awk_strverscmp" v1="$1" v2="$2" /dev/null
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+    case $? in
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+      1)  echo '<';;
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+      0)  echo '=';;
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+      2)  echo '>';;
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+    esac
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+  )
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+}
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+
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+
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+__require_tool_fatal ()
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+{
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+    echo $@ >/dev/stderr
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+    return 1
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+}
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+
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+# Usage: require_tool program version
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+# Returns: 0 if $1 version if greater equals than $2, 1 otherwise.
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+# In case of error, message is written on error output.
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+#
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+# Example: require_tool gcc 4.6
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+# Use GCC environment variable if defined instead of lookup for the tool
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+# in the environment.
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+require_tool ()
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+{
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+  envvar_name=$(echo $1 | tr '[:lower:]' '[:upper:]')
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+  tool=$(printenv $envvar_name || echo $1)
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+  local version=$($tool --version 2>/dev/null| \
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+    sed -n 's/.*[^0-9.]\([0-9]*\.[0-9.]*\).*/\1/p;q')
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+  if test x"$version" = x ; then
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+      echo "$tool is required" >/dev/stderr
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+      return 1
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+  fi
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+  case $(__require_tool_version_compare "$2" "$version") in
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+    '>')
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+	  echo "$1 $2 or better is required: this is $tool $version" >/dev/stderr
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+	  return 1
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+	  ;;
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+  esac
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+}
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+
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+usage() {
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+    cat <<EOF
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+NAME
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+    require_tool.sh - Ensure version of a tool is greater than the one expected
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+
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+SYNOPSYS
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+    require_tool.sh [ -h ]
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+                    [ --help ]
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+                    [ TOOL MIN_VERSION ]
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+
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+DESCRIPTION
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+    TOOL is the name or path of the program to check. If the name is specified, its
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+    path is deduced from PATH environment variable. If environment variable TOOL
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+    (in upper-case characters) is defined, considers its value as path to the tool.
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+
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+    MIN_VERSION is a string representing the minimum required version.
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+
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+BEHAVIOR
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+    * locate path to the program.
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+    * execute $ TOOL_PATH --version
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+    * extract version from standard output.
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+    * compare this version to the expected one.
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+
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+OPTIONS
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+    -h --help
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+        Display this message and exit 0
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+
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+ERRORS
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+    if program is not found or its version is prior to expected version,
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+    a message is written to error output.
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+
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+EXIT VALUE
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+    returns 0 if program version if greater equals than expected version,
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+    returns 1 otherwise.
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+
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+EXAMPLE
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+    $ require_tool.sh emacs 23
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+    $ CC=g++ require_tool.sh cc 4.6
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+    $ require_tool.sh zsh 4.5
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+
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+EOF
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+}
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+
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+for arg in $@; do
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+    case $arg in
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+        -h|--help)
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+            usage
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+            exit 0
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+            ;;
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+    esac
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+done
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+if [ $# -gt 2 ] ; then
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+    echo "ERROR: expecting 2 parameters. Please see option --help"
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+    exit 1
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+fi
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+
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+require_tool $@