utils.sh

#!/bin/bash
#
# This utility script houses some common environment-checking code meant to
# make scripts more robust. Includes functions to attempt to find files and
# folders in current directory, as well as crawl through dependencies and
# blacklists.
#
# Author: Solis Knight
# Date: July 2013
#
#

VERSION="2.1"

# Exit Error Codes
SUCCESS=0
WRONG_NUMBER_ARGUMENTS=1
BAD_ARGUMENTS=2
NOT_FOUND=3
BLACKLIST_VIOLATED=4
FAILURE=5

# Function see
# Attempts to find an item, given a qualified name. (Including path)
#
# Arguments: 2
# $1: Mode: either "file" or "dir"
# Note: if the file is a symbolic link, it will be reported as found on either mode.
# $2: Name: name of file or directory to see
#
# Returns: 4
# $SUCCESS - item was found.
# $WRONG_NUMBER_ARGUMENTS - there were not exactly 2 arguments provided.
# $BAD_ARGUMENTS - The first argument was not a valid record type.
# $NOT_FOUND - The item was not found.
#
# Author: Solis Knight
# Date: July 2013
function see() {
    if [[ $# != 2 ]]; then
        return $WRONG_NUMBER_ARGUMENTS
    fi

    if [[ ! -e "$2" ]]; then
        return $NOT_FOUND
    fi

    if [[ "$1" == "file" ]]; then
        if [[ ! -f "$2" && ! -L "$2" ]]; then
            return $NOT_FOUND
        fi

    elif [[ "$1" == "dir" ]]; then
        if [[ ! -d "$2" && ! -L "$2" ]]; then
            return $NOT_FOUND
        fi
    else
        return $BAD_ARGUMENTS
    fi

    return $SUCCESS
}

# Function check
# Crawls through a list of files or directories, and reports issues. Supports
# dependency checks and blacklisting.
# Dependencies will throw an error if not found.
# Blacklisted items will throw an error if found.
#
# Arguments: 3
# $1: Mode: either "dependency" or "blacklist"
# $2: Type: either "file" or "dir" - see function "see"
# $3: Names: list of files or directories to check
#
# Returns: 5
# $SUCCESS - dependencies satisfied, blacklist not violated.
# $WRONG_NUMBER_ARGUMENTS - there were not exactly 3 arguments provided.
# $BAD_ARGUMENTS - The mode or type specified was not valid.
# $NOT_FOUND - A required dependency was not found.
# $BLACKLIST_VIOLATED - A blacklisted item was found.
#
# Author: Solis Knight
# Date: July 2013
function check() {
	if [[ $# != 3 ]]; then
                return $WRONG_NUMBER_ARGUMENTS
        fi

	DEPENDENCY=0
	BLACKLIST=1

	case "$1" in
	"dependency" )
		MODE=$DEPENDENCY;;
	"blacklist" )
		MODE=$BLACKLIST;;
	*)
		return $BAD_ARGUMENTS
	esac

	for item in $3; do
		see "$2" "$item"
		retval=$?
		case $retval in
		$WRONG_NUMBER_ARGUMENTS )
			return $retval;;
		$BAD_ARGUMENTS )
			return $retval;;
		$NOT_FOUND )
			if [[ $MODE = $DEPENDENCY ]]; then
				echo "Required dependency $item was not found."
				return $NOT_FOUND
			fi 
			;;
		$SUCCESS )
			if [[ $MODE = $BLACKLIST ]]; then
				echo "Blacklsited $1 $item was found."
				return $BLACKLIST_VIOLATED
			fi
			;;
		*)
			return $NOT_FOUND
		esac
        done
	return $SUCCESS
}

# Function cdHere
# Normalizes the current working directory by moving to the directory of the 
# calling script.
#
# Arguments: 1
# $1: Script path - this function should be called with "$0" as the argument.
#
# Returns: 4
# $SUCCESS - Successful cd
# $WRONG_NUMBER_ARGUMENTS - there was not exactly 1 argument provided.
# $BAD_ARGUMENTS - the argument did not contain enough path information.
# $? - If cd returns an error, it will be passed to the caller.
#
# Author: Solis Knight
# Date: July 2013
function cdHere() {
	if [[ $# != 1 ]]; then
	   return $WRONG_NUMBER_ARGUMENTS
	fi

	if [[ `echo $1 | grep "/" | wc -l` > 0 ]]; then
		cd ${1%/*}
		return $?
	else
	   return $BAD_ARGUMENTS
	fi
}

# Function currentBranch
# Stores the name of the current git branch into the passed-in variable.
#
# Arguments: 1
# $1: Return_val - variable to store the branch name into.
#
# Returns: 1
# $SUCCESS - Successful `git branch`
# $WRONG_NUMBER_ARGUMENTS - there was not exactly 1 argument provided.
# $? - If `git branch` returns an error, it will be passed to the caller.
#
# Author: Solis Knight
# Date: July 2013
function currentBranch() {
	#if [[ $# != 1 ]]; then
	#	return $WRONG_NUMBER_ARGUMENTS
    #fi

	# Store the name of the current branch into the passed-in variable
	#Command Substitution Method
	OUTPUT=`git branch`
	if [[ $? != 0 ]]; then return $?; fi
	OUTPUT=${OUTPUT##*\*\ }
	OUTPUT=${OUTPUT%%[[:space:]]*}
	eval "$1=$OUTPUT"
	return $SUCCESS

	# Store the name of the current branch into passed-in variable
	# Grep | Sed method
	#eval "$1=`git branch | grep "^\*" | sed "s/..//"`"
	#return $SUCCESS
}

# Function mkdirs
# Attempts to create the directory structure implied by the given path. Will
# create all intermediate directories required.
#
# Arguments: 1
# $1: path - Absolute path to create directory structure for
#
# Returns: 1
# $SUCCESS - Successful `git branch`
# $WRONG_NUMBER_ARGUMENTS - there was not exactly 1 argument provided.
# $? - If `mkdir` returns an error at any point, it will be passed to the
# caller. Successful directory creation will remain in an event of an error.
#
# Author: Solis Knight
# Date: July 2013
function mkdirs() {
	if [[ $# != 1 ]]; then
		return $WRONG_NUMBER_ARGUMENTS
    fi

	if [[ -z $1 ]]; then
		echo "Paramter 1 is of zero length!"
		return;
	else
		mkdirs ${1%/*}
		retval=$?
		if [[ $retval == $FAILURE ]]; then
			return $FAILURE
		fi 
		see dir "$1"
		retval=$?
		if [[ $retval == $NOT_FOUND ]]; then  
			mkdir $1
			retval=$?
			if [[ $retval != 0 ]]; then
				return $FAILURE
			fi
		fi
	fi		

}