Gumby.Install

0.0.1.0

Gumby.Install.psm1

using module Gumby.File
using module Gumby.Log

# Future:
# - change functions to push inverse operation onto stack, thereby enabling roll-back and automatic
# generation of uninstall scripts

function IsCurrentUserAdmin() {
    return ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole(
        [Security.Principal.WindowsBuiltInRole]::Administrator)
}

# alternative names:
# EnsureDirectory
function CreateDirectoryIfNotExisting($Path) {
    if (!(Test-Path $Path)) {
        [Log]::Comment("creating directory `"$Path`"")
        [void](mkdir $Path)
    } else {
        [Log]::Comment("skipping creation of directory `"$Path`" because it exists")
    }
}

function RemoveDirectoryIfExistingAndEmpty($Path) {
    if (Test-Path -PathType Container $Path) {
        $dirInfo = Get-Item $Path
        if (($dirInfo.GetDirectories().Count + $dirInfo.GetFiles().Count) -eq 0) {
            [Log]::Comment("removing directory `"$Path`"")
            rmdir $Path
        } else {
            [Log]::Comment("skipping removal of directory `"$Path`" because it is not empty")
        }
    } else {
        [Log]::Comment("skipping removal of directory `"$Path`" because it does not exist")
    }
}

# alternative names:
# EnsureSymbolicLink
function CreateSymbolicLinkIfNotExisting($Link, $Target) {
    if (!(Test-Path $Target)) {
        $errorMessage = "link target `"$Target`" does not exist"
        [Log]::Error($errorMessage)
        throw $errorMessage
    }

    if ($Target -is [string]) { $Target = Get-Item $Target }

    if (Test-Path $Link) {
        if ($Link -is [string]) { $Link = Get-Item $Link }

        if (IsSymbolicLink $Link) {
            if ($Link.Target[0] -eq $Target.FullName) {
                [Log]::Comment("skipping creation of symbolic link from `"$Link`" to `"$Target`" because it exists")
            } else {
                [Log]::Comment("re-targeting symbolic link `"$Link`" to `"$Target`"")
                Remove-Item -Force $Link
                # requires admin privileges
                CreateSymbolicLink -Target $Target -Link $Link
            }
        } else {
            [Log]::Comment("overwriting file at `"$Link`" with link to `"$Target`"")
            Remove-Item -Force $Link
            # requires admin privileges
            CreateSymbolicLink -Target $Target -Link $Link
        }
    } else {
        [Log]::Comment("creating symbolic link `"$Link`" targeting `"$Target`"")
        # requires admin privileges
        CreateSymbolicLink -Target $Target -Link $Link
    }
}

function CopyFileIfTargetNotExistingOrIsOlder($Source, $Target) {
    if (!(Test-Path $Source)) {
        $errorMessage = "source of copy operation `"$Source`" does not exist"
        [Log]::Error($errorMessage)
        throw $errorMessage
    }

    if (!(Test-Path $Target)) {
        [Log]::Comment("copying `"$Source`" to `"$Target`" because target does not exist")
        Copy-Item $Source $Target
    } else {
        $sourceTime = (Get-Item $Source).LastWriteTime
        $targetTime = (Get-Item $Target).LastWriteTime
        if ($sourceTime -gt $targetTime) {
            [Log]::Comment("copying `"$Source`" to `"$Target`" because target is outdated")
            Copy-Item $Source $Target
        } else {
            [Log]::Comment("skipping copying of `"$Source`" to `"$Target`" because target is up to date")
        }
    }
}

# alternative names:
# EnsureFileRemoved
function RemoveFileIfExisting($Path) {
    if (Test-Path $Path) {
        [Log]::Comment("removing file `"$Path`"")
        Remove-Item $Path
    } else {
        [Log]::Comment("skipping removal of file `"$Path`" because it does not exist")
    }
}