Add a Powershell install script

  * Fixes twpayne#1006

assets/scripts/install.ps1

@@ -0,0 +1,285 @@
+#Requires -Version 5
+enum LogLevel {
+    Debug = 3
+    Info = 2
+    Error = 1
+    Critical = 0
+}
+
+$old_eap = $ErrorActionPreference
+$ErrorActionPreference = 'Stop' # throw an exception if anything bad happens
+
+# If the environment isn't correct for running this script, try to give people
+# some idea of how to fix it
+
+if (($PSVersionTable.PSVersion.Major) -lt 5) {
+    Write-Warning "PowerShell 5 or later is required to run this install script."
+    Write-Warning "Please upgrade: https://docs.microsoft.com/en-us/powershell/scripting/setup/installing-windows-powershell"
+    break
+}
+
+# show notification to change execution policy:
+$allowedExecutionPolicy = @('Unrestricted', 'RemoteSigned', 'Bypass')
+if ((Get-ExecutionPolicy).ToString() -notin $allowedExecutionPolicy) {
+    Write-Warning "PowerShell requires an execution policy in [$($allowedExecutionPolicy -join ", ")] to run this install script."
+    Write-Warning "For example, to set the execution policy to 'RemoteSigned' please run :"
+    Write-Warning "'Set-ExecutionPolicy RemoteSigned -scope CurrentUser'"
+    break
+}
+
+# globals
+$tempdir = (Join-Path ([IO.Path]::GetTempPath()) ([IO.Path]::GetRandomFileName()));
+
+# Helper functions
+function Fetch-FileFromWeb(
+    [string]$url,
+    [string]$path
+) {
+    $cl = New-Object Net.WebClient
+    $cl.Headers['User-Agent'] = 'System.Net.WebClient'
+    $cl.DownloadFile($url, $path)
+}
+
+function Fetch-StringFromWeb(
+    [string]$url
+) {
+    $cl = New-Object Net.WebClient
+    $cl.Headers['User-Agent'] = 'System.Net.WebClient'
+    return $cl.DownloadString($url)
+}
+
+function Fetch-JsonFromWeb(
+    [string]$url
+) {
+    $cl = New-Object Net.WebClient
+    $cl.Headers['User-Agent'] = 'System.Net.WebClient'
+    $cl.Headers['Accept'] = 'application/json'
+    return $cl.DownloadString($url) | ConvertFrom-Json
+}
+
+function Fetch-DataFromWeb(
+    [string]$url
+) {
+    $cl = New-Object Net.WebClient
+    $cl.Headers['User-Agent'] = 'System.Net.WebClient'
+    return $cl.DownloadData($url)
+}
+
+function log {
+    [CmdletBinding(PositionalBinding=$false)]
+    param(
+        [LogLevel] $MessageLevel,
+        [string] $Message
+    )
+
+    if ([int]$LogLevel -ge [int]$MesageLevel) {
+        Write-Host $Message
+    }
+}
+
+function log-debug {
+    param(
+        [string] $Message
+    )
+    log -MessageLevel Debug -Message $Message
+}
+
+function log-info {
+    param(
+        [string] $Message
+    )
+    log -MessageLevel Info -Message $Message
+}
+
+function log-error {
+    param(
+        [string] $Message
+    )
+    log -MessageLevel Error -Message $Message
+}
+
+function log-critical {
+    param(
+        [string] $Message
+    )
+    log -MessageLevel Critical -Message $Message
+}
+
+function get_goos {
+    $ri = [System.Runtime.InteropServices.RuntimeInformation]::IsOSPlatform;
+    if ($ri.Invoke([Runtime.InteropServices.OSPlatform]::Windows)) {
+        return "windows"
+    } elseif ($ri.Invoke([Runtime.InteropServices.OSPlatform]::Linux)) {
+        return "linux"
+    } elseif ($ri.Invoke([Runtime.InteropServices.OSPlatform]::OSX)) {
+        return "darwin"
+    } elseif ($ri.Invoke([Runtime.InteropServices.OSPlatform]::FreeBSD)) {
+        return "freebsd"
+    } else {
+        throw "unsupported platform"
+    }
+}
+
+function get_goarch {
+    # convert these to strings because the enums don't apparently work in switch TODO: is this fixable?
+    switch ("$([Runtime.InteropServices.RuntimeInformation]::OSArchitecture)") {
+        "$([Runtime.InteropServices.Architecture]::Arm)" {
+            return "arm"
+        }
+        "$([Runtime.InteropServices.Architecture]::Arm64)" {
+            return "arm64"
+        }
+        "$([Runtime.InteropServices.Architecture]::X86)" {
+            return "i386"
+        }
+        "$([Runtime.InteropServices.Architecture]::X64)" {
+            return "amd64"
+        }
+        default {
+            throw "unsupported architecture: $_"
+        }
+    }
+}
+
+function get-real-tag {
+    param(
+        [string] $tag
+    )
+
+    log-debug "checking GitHub for tag $tag"
+
+    $release_url = "https://github.com/twpayne/chezmoi/releases/$tag"
+    $real_tag = (Fetch-JsonFromWeb $release_url).tag_name
+
+    log-debug "found tag $real_tag for $tag"
+    return $real_tag
+}
+
+function verify-hash {
+    param(
+        [string] $target,
+        [string] $checksums
+    )
+
+    $basename = [IO.Path]::GetFileName($target);
+
+    # what checksum are we looking for?
+    $want = (Get-Content $checksums | ForEach-Object {
+        $line = $_;
+        if ($line -match "$($basename)$") {
+            $hash, $name = ($line -split "\s+");
+            return $hash;
+        }
+    } | Select-Object -First 1).ToLower();
+
+    $got = (Get-FileHash -LiteralPath $target -Algorithm SHA256).Hash.ToLower();
+
+    if ($want -ne $got) {
+        Write-Error "Wanted: $want"
+        Write-Error "Got: $got"
+        throw "Checksum mismatch!"
+    }
+}
+
+function unpack-file {
+    param(
+        [string] $file
+    )
+
+    if ($file.EndsWith(".tar.gz") -or $file.EndsWith(".tgz")) {
+        tar -xzf $file
+    } elseif ($file.EndsWith(".tar")) {
+        tar -xf $file
+    } elseif ($file.EndsWith(".zip")) {
+        unzip $file
+    } else {
+        throw "can't unpack unknown format for $file"
+    }
+}
+
+function main {
+    [CmdletBinding(PositionalBinding=$false)]
+    param(
+        [Parameter(Mandatory = $false)]
+        [string] $BinDir = (Join-Path (Resolve-Path '.') 'bin'),
+
+        [Parameter(Mandatory = $false)]
+        [string] $Tag = 'latest',
+
+        [LogLevel] $LogLevel = [LogLevel]::Info,
+
+        [Parameter(ValueFromRemainingArguments = $true)]
+        [string[]]$ExecArgs
+    )
+
+    # $BinDir = Resolve-Path $BinDir
+
+    $os = get_goos
+    $arch = get_goarch
+    $real_tag = get-real-tag $Tag
+    $version = if ($real_tag.StartsWith("v")) { $real_tag.Substring(1) } else { $real_tag };
+
+    log-info "found version $version for $Tag/$os/$arch"
+
+    $binsuffix = ""
+    $format = "tar.gz"
+
+    if ($os -eq "windows") {
+        $binsuffix = ".exe"
+        $format = "zip"
+    }
+
+    $github_download = "https://github.com/twpayne/chezmoi/releases/download"
+    New-Item -Type Directory -Path $tempdir | Out-Null
+
+    # download tarball
+    $name="chezmoi_$($version)_$($os)_$($arch)"
+    $tarball="$name.$format"
+    $tarball_url="$($github_download)/$real_tag/$tarball"
+
+    $tmp_tarball = (Join-Path $tempdir $tarball)
+    Fetch-FileFromWeb $tarball_url $tmp_tarball
+
+    # download checksums
+    $checksums = "chezmoi_$($version)_checksums.txt"
+    $checksums_url = "$($github_download)/$($real_tag)/$($checksums)"
+
+    $tmp_checksums = (Join-Path $tempdir $checksums)
+    Fetch-FileFromWeb $checksums_url $tmp_checksums
+
+    # verify checksums
+    verify-hash $tmp_tarball $tmp_checksums
+
+    Push-Location $tempdir
+
+    unpack-file $tarball
+
+    # install the binary
+    if (-not (Test-Path $BinDir)) {
+        New-Item -Type Directory -Path $BinDir | Out-Null
+    }
+
+    $binary = "chezmoi$($binsuffix)";
+    $tmp_binary = (Join-Path $tempdir $binary);
+
+    Move-Item -Path $tmp_binary -Destination $BinDir
+
+    log-info "Installed $($BinDir)/$($binary)"
+
+    if ($ExecArgs) {
+        & "$($BinDir)/$($binary)" $ExecArgs
+    }
+}
+
+try {
+    Invoke-Expression ("main " + $params)
+} catch {
+    Write-Host "An error occurred while installing: $_"
+} finally {
+    Pop-Location
+
+    if (Test-Path $tempdir) {
+        Remove-Item -LiteralPath $tempdir -Recurse -Force
+    }
+}
+

docs/INSTALL.md

@@ -16,6 +16,10 @@ with a single command.
 
     curl -sfL https://git.io/chezmoi | sh
 
+Or on systems with Powershell, you can use this command:
+
+    (iwr https://git.io/chezmoi.ps1).Content | powershell -c -
+
 ## One-line package install
 
 Install chezmoi with a single command.

internal/cmd/lint-whitespace/main.go

@@ -19,6 +19,7 @@ var (
 		regexp.MustCompile(`\.svg\z`),
 		regexp.MustCompile(`\A\.devcontainer/library-scripts\z`),
 		regexp.MustCompile(`\A\.git\z`),
+		regexp.MustCompile(`\Aassets/scripts/install\.ps1\z`),
 		regexp.MustCompile(`\Achezmoi2/completions/chezmoi\.ps1\z`),
 		regexp.MustCompile(`\Acompletions/chezmoi\.ps1\z`),
 		regexp.MustCompile(`\Achezmoi\.io/public\z`),