Initial implementation

README.md

@@ -0,0 +1,183 @@
+# gitprompt
+
+gitprompt is a configurable, fast and zero-dependencies* way of getting the
+current git status to be displayed in the `PROMPT`.
+
+Displays:
+
+- Current branch / sha1
+- Untracked files
+- Modified files
+- Staged files
+- Commits behind / ahead remote
+
+When executed, gitprompt gets the git status of the current working directory
+then prints it according to the format specified. If the current working
+directory is not part of a git repository, gitprompt
+exits with code `0` and no output.
+
+`*` git is required
+
+## Configuration
+
+The output is configured with `-format` or the `GITPROMPT_FORMAT` environment
+variable. If both are set, the flag takes precedence.
+
+A very bare-bones format can look like this:
+
+```
+gitprompt -format="%h >%s ↓%b ↑%a @%c +%m %u"
+
+# or
+
+export GITPROMPT_FORMAT="%h >%s ↓%b ↑%a @%c +%m %u"
+gitprompt
+```
+
+Characters that don't have a special meaning are printed as usual _(unicode
+characters are fine, go crazy with emojis if that's your thing)_.
+
+### Data
+
+Various data from git can be displayed in the output. Data tokens are prefixed
+with `%`:
+
+| token | explanation                       |
+|-------|-----------------------------------|
+| `%h`  | Current branch or sha1            |
+| `%s`  | Number of files staged            |
+| `%b`  | Number of commits behind remote   |
+| `%a`  | Number of commits ahead of remote |
+| `%c`  | Number of conflicts               |
+| `%m`  | Number of files modified          |
+| `%u`  | Number of untracked files         |
+
+Normally `%h` displays the current branch (`master`) but if you're detached
+from `HEAD`, it will display the current sha1. Only first 7 characters of the
+sha1 are displayed.
+
+### Colors
+
+The color can be set with color tokens, prefixed with `#`:
+
+| token | color             |
+|-------|-------------------|
+| `#k`  | Black             |
+| `#r`  | Red               |
+| `#g`  | Green             |
+| `#y`  | Yellow            |
+| `#b`  | Blue              |
+| `#m`  | Magenta           |
+| `#c`  | Cyan              |
+| `#w`  | White             |
+| `#K`  | Highlight Black   |
+| `#R`  | Highlight Red     |
+| `#G`  | Highlight Green   |
+| `#Y`  | Highlight Yellow  |
+| `#B`  | Highlight Blue    |
+| `#M`  | Highlight Magenta |
+| `#C`  | Highlight Cyan    |
+| `#W`  | Highlight White   |
+
+The color is set until another color overrides it, or a group ends (see below).
+If a color was set when gitprompt is done, it will add a color reset escape
+code at the end, meaning text after gitprompt won't have the color applied.
+
+### Text attributes
+
+The text attributes can be set with attribute tokens, prefixed with `@`:
+
+| token | attribute             |
+|-------|-----------------------|
+| `@b`  | Set bold              |
+| `@B`  | Clear bold            |
+| `@f`  | Set faint/dim color   |
+| `@F`  | Clear faint/dim color |
+| `@i`  | Set italic            |
+| `@I`  | Clear italic          |
+
+As with colors, if an attribute was set when gitprompt is done, an additional
+escape code is automatically added to clear it.
+
+### Groups
+
+Groups can be used for adding logic to the format. A group's output is only
+printed if at least one item in the group has data.
+
+| token | action      |
+|-------|-------------|
+| `[`   | start group |
+| `]`   | end group   |
+
+Consider the following:
+
+```
+%h[ %a][ %m]
+```
+
+With `head=master, ahead=3, modified=0`, this will print `master 3` since there
+were not modified files. Note the space that's included in the group, if
+spacing should be added when the group is present, the spacing should be added
+to the group itself.
+
+Colors and attributes are also scoped to a group, meaning they won't leak
+outside so there's no need to reset colors:
+
+```
+[#r behind: %b] - [#g ahead: %a]
+```
+
+This prints `behind` in red, `-` without any formatting, and `ahead` in green.
+
+```
+#c%h[ >%s][ ↓%b ↑%a]
+```
+
+This prints the current branch/sha1 in cyan, then number of staged files (if
+not zero), then commits behind and ahead (if both are not zero). This allows
+for symmetry, if it's desired to show `master >1 ↓0 ↑2` instead of `master >1
+↑2`.
+
+### Complete example
+
+Putting everything together, a complex format may look something like this:
+
+```
+gitprompt -format="#B(@b#R%h[#y >%s][#m ↓%b ↑%a][#r x%c][#g +%m][#y ϟ%u]#B)"
+```
+
+- `(` in highlight blue
+- Current branch/sha1 in bold red
+- If there are staged files, number of staged files in yellow, prefixed with `>`
+- If there are commits ahead or behind, show them with arrows in magenta
+- If there are conflicts, show them in red, prefixed with `x`
+- If files have been modified since the previous commit, show `+3` for 3 modified files
+- If files are untracked (added since last commit), show a lightning and the number in yellow
+- `)` in highlight blue
+- _any text printed after gitprompt will have all formatting cleared_
+
+## Download
+
+### MacOS
+
+Install [Homebrew]
+
+`TODO(akupila): brew cask`
+
+## Configure your shell
+
+### zsh
+
+gitprompt needs to execute as a part the `PROMPT`, add this to your `~/.zshrc`:
+
+```
+PROMPT='$(gitprompt)'
+```
+
+Now reload the config (`source ~/.zshrc`) and gitprompt should show up. Of
+course you're free to add anything else here too, just execute `gitprompt`
+where you want the status.
+
+
+
+[Homebrew]: https://brew.sh/

cmd/gitprompt/gitprompt.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"flag"
+	"os"
+
+	"github.com/akupila/gitprompt"
+)
+
+const defaultFormat = "#B([@b#R%h][#y ›%s][#m ↓%b][#m ↑%a][#r x%c][#g +%m][#y %u]#B)"
+
+type formatFlag struct {
+	set   bool
+	value string
+}
+
+func (f *formatFlag) Set(v string) error {
+	f.set = true
+	f.value = v
+	return nil
+}
+
+func (f *formatFlag) String() string {
+	if f.set {
+		return f.value
+	}
+
+	if envVar := os.Getenv("GITPROMPT_FORMAT"); envVar != "" {
+		return envVar
+	}
+
+	return defaultFormat
+}
+
+var format formatFlag
+
+func main() {
+	flag.Var(&format, "format", formatHelp())
+	flag.Parse()
+	gitprompt.Exec(format.String())
+}

cmd/gitprompt/help.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/akupila/gitprompt"
+)
+
+var exampleStatus = &gitprompt.GitStatus{
+	Branch:    "master",
+	Sha:       "0455b83f923a40f0b485665c44aa068bc25029f5",
+	Untracked: 1,
+	Modified:  2,
+	Staged:    3,
+	Conflicts: 4,
+	Ahead:     5,
+	Behind:    6,
+}
+
+var formatHelp = func() string {
+	return strings.TrimSpace(fmt.Sprintf(`
+How to format output
+
+Default format is: %q
+Example result:    %s
+
+Data:
+	%%h	Current branch or SHA1
+	%%s	Number of files staged
+	%%b	Number of commits behind remote
+	%%a	Number of commits ahead of remote
+	%%c	Number of conflicts
+	%%m	Number of files modified
+	%%u	Number of untracked files
+
+Colors:
+	#k	Black
+	#r	Red
+	#g	Green
+	#y	Yellow
+	#b	Blue
+	#m	Magenta
+	#c	Cyan
+	#w	White
+	#K	Highlight Black
+	#R	Highlight Red
+	#G	Highlight Green
+	#Y	Highlight Yellow
+	#B	Highlight Blue
+	#M	Highlight Magenta
+	#C	Highlight Cyan
+	#W	Highlight White
+
+Text attributes:
+	@b	Set bold
+	@B	Clear bold
+	@f	Set faint/dim color
+	@F	Clear faint/dim color
+	@i	Set italic
+	@I	Clear italic
+`, defaultFormat, gitprompt.Print(exampleStatus, defaultFormat)))
+}

formatter.go

@@ -0,0 +1,96 @@
+package gitprompt
+
+import (
+	"bytes"
+	"strconv"
+	"strings"
+)
+
+type formatter struct {
+	color        uint8
+	currentColor uint8
+	attr         uint8
+	currentAttr  uint8
+}
+
+func (f *formatter) setColor(c uint8) {
+	f.color = c
+}
+
+func (f *formatter) clearColor() {
+	f.color = 0
+}
+
+func (f *formatter) setAttribute(a uint8) {
+	f.attr |= (1 << a)
+}
+
+func (f *formatter) clearAttribute(a uint8) {
+	f.attr &= ^(1 << a)
+}
+
+func (f *formatter) attributeSet(a uint8) bool {
+	return (f.attr & (1 << a)) != 0
+}
+
+func (f *formatter) clearAttributes() {
+	f.attr = 0
+}
+
+func (f *formatter) printANSI(b *bytes.Buffer) {
+	if f.color == f.currentColor && f.attr == f.currentAttr {
+		return
+	}
+	b.WriteString("\x1b[")
+	if f.color == 0 && f.attr == 0 {
+		// reset all
+		b.WriteString("0m")
+		f.currentColor = 0
+		f.currentAttr = 0
+		return
+	}
+	mm := []string{}
+	aAdded, aRemoved := attrDiff(f.currentAttr, f.attr)
+	if len(aRemoved) > 0 {
+		mm = append(mm, "0")
+		var i uint8 = 1
+		for ; i < 8; i++ {
+			if f.attributeSet(i) {
+				mm = append(mm, strconv.Itoa(int(i)))
+			}
+		}
+	} else if len(aAdded) > 0 {
+		for _, a := range aAdded {
+			mm = append(mm, strconv.Itoa(int(a)))
+		}
+	}
+	if f.color != f.currentColor || len(aRemoved) > 0 {
+		mm = append(mm, strconv.Itoa(int(f.color)))
+	}
+	b.WriteString(strings.Join(mm, ";"))
+	b.WriteString("m")
+	f.currentColor = f.color
+	f.currentAttr = f.attr
+
+}
+
+func attrDiff(a, b uint8) ([]uint8, []uint8) {
+	added := []uint8{}
+	removed := []uint8{}
+	var i uint8
+	for ; i < 8; i++ {
+		inA := (a & (1 << i)) != 0
+		inB := (b & (1 << i)) != 0
+		if inA && inB {
+			continue
+		}
+		if inB {
+			added = append(added, i)
+			continue
+		}
+		if inA {
+			removed = append(removed, i)
+		}
+	}
+	return added, removed
+}