Start plugin support and plugin manager

cmd/micro/manager/parser.go

@@ -0,0 +1,149 @@
+package manager
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"path"
+
+	"github.com/blang/semver"
+	"github.com/zyedidia/micro/cmd/micro/config"
+	git "gopkg.in/src-d/go-git.v4"
+)
+
+var (
+	ErrMissingName     = errors.New("Missing or empty name field")
+	ErrMissingDesc     = errors.New("Missing or empty description field")
+	ErrMissingSite     = errors.New("Missing or empty website field")
+	ErrMissingRepo     = errors.New("Missing or empty repository field")
+	ErrMissingVersions = errors.New("Missing or empty versions field")
+	ErrMissingTag      = errors.New("Missing or empty tag field")
+	ErrMissingRequire  = errors.New("Missing or empty require field")
+)
+
+type Plugin struct {
+	info *PluginInfo
+	dir  string
+	repo *git.Repository
+	// Index into info.Versions showing the current version of this plugin
+	Version int
+}
+
+// PluginVersion describes a version for a plugin as well as any dependencies that
+// version might have
+// This marks a tag that corresponds to the version in the git repo
+type PluginVersion struct {
+	Vers    semver.Version
+	Vstr    string            `json:"version"`
+	Tag     string            `json:"tag"`
+	Require map[string]string `json:"require"`
+}
+
+// PluginInfo contains all the needed info about a plugin
+type PluginInfo struct {
+	Name     string          `json:"name"`
+	Desc     string          `json:"description"`
+	Site     string          `json:"website"`
+	Repo     string          `json:"repository"`
+	Versions []PluginVersion `json:"versions"`
+}
+
+// NewPluginInfo parses a JSON input into a valid PluginInfo struct
+// Returns an error if there are any missing fields or any invalid fields
+// There are no optional fields in a plugin info json file
+func NewPluginInfo(data []byte) (*PluginInfo, error) {
+	var info PluginInfo
+
+	dec := json.NewDecoder(bytes.NewReader(data))
+	dec.DisallowUnknownFields() // Force errors
+
+	if err := dec.Decode(&info); err != nil {
+		return nil, err
+	}
+
+	if len(info.Name) == 0 {
+		return nil, ErrMissingName
+	} else if len(info.Desc) == 0 {
+		return nil, ErrMissingDesc
+	} else if len(info.Site) == 0 {
+		return nil, ErrMissingSite
+	} else if len(info.Repo) == 0 {
+		return nil, ErrMissingRepo
+	} else if err := info.makeVersions(); err != nil {
+		return nil, err
+	}
+
+	return &info, nil
+}
+
+func (i *PluginInfo) makeVersions() error {
+	if len(i.Versions) == 0 {
+		return ErrMissingVersions
+	}
+
+	for _, v := range i.Versions {
+		sv, err := semver.Make(v.Vstr)
+		if err != nil {
+			return err
+		}
+		v.Vers = sv
+		if len(v.Tag) == 0 {
+			return ErrMissingTag
+		} else if v.Require == nil {
+			return ErrMissingRequire
+		}
+	}
+
+	return nil
+}
+
+// InstalledPlugins searches the config directory for all installed plugins
+// and returns the list of plugin infos corresponding to them
+func ListInstalledPlugins() ([]*Plugin, error) {
+	pdir := path.Join(config.ConfigDir, "plugin")
+
+	files, err := ioutil.ReadDir(pdir)
+	if err != nil {
+		return nil, err
+	}
+
+	var plugins []*Plugin
+
+	for _, dir := range files {
+		if dir.IsDir() {
+			files, err := ioutil.ReadDir(path.Join(pdir, dir.Name()))
+			if err != nil {
+				return nil, err
+			}
+
+			for _, f := range files {
+				if f.Name() == "repo.json" {
+					dat, err := ioutil.ReadFile(path.Join(pdir, dir.Name(), "repo.json"))
+					if err != nil {
+						return nil, err
+					}
+					info, err := NewPluginInfo(dat)
+					if err != nil {
+						return nil, err
+					}
+
+					dirname := path.Join(pdir, dir.Name())
+					r, err := git.PlainOpen(dirname)
+					if err != nil {
+						return nil, err
+					}
+
+					p := &Plugin{
+						info: info,
+						dir:  dirname,
+						repo: r,
+					}
+
+					plugins = append(plugins, p)
+				}
+			}
+		}
+	}
+	return plugins, nil
+}