Render git diffs

4 files changed, 187 insertions, 2 deletions

diff --git a/lib/serve.js b/lib/serve.js
index f146c49..de2757e 100644
--- a/lib/serve.js
+++ b/lib/serve.js
@@ -23,6 +23,7 @@ var emojis = require('emoji-named-characters')
 var jpeg = require('jpeg-autorotate')
 var unzip = require('unzip')
 var Catch = require('pull-catch')
+var Diff = require('diff')
 
 module.exports = Serve
 
@@ -1648,6 +1649,7 @@ Serve.prototype.git = function (url) {
     case 'tree': return this.gitTree(m[2])
     case 'blob': return this.gitBlob(m[2])
     case 'raw': return this.gitRaw(m[2])
+    case 'diff': return this.gitDiff(m[2])
     default: return this.respond(404, 'Not found')
   }
 }
@@ -1782,10 +1784,14 @@ Serve.prototype.gitCommit = function (rev) {
               pull.map(function (file) {
                 return ph('tr', [
                   ph('td', ph('code', u.escapeHTML(file.name))),
-                  // ph('td', ph('code', u.escapeHTML(JSON.stringify(file.msg)))),
                   ph('td', file.deleted ? 'deleted'
                          : file.created ? 'created'
-                         : file.hash ? 'changed'
+                         : file.hash ?
+                    ph('a', {href:
+                      self.app.render.toUrl('/git/diff/'
+                        + file.hash[0] + '..' + file.hash[1]
+                        + '?msg=' + encodeURIComponent(obj.msg.key))
+                    }, 'changed')
                          : file.mode ? 'mode changed'
                          : JSON.stringify(file))
                 ])
@@ -2016,6 +2022,177 @@ Serve.prototype.gitBlob = function (rev) {
   })
 }
 
+Serve.prototype.gitDiff = function (revs) {
+  var self = this
+  var parts = revs.split('..')
+  if (parts.length !== 2) return pull(
+    ph('div.error', 'revs should be <rev1>..<rev2>'),
+    self.wrapPage('git diff'),
+    self.respondSink(400)
+  )
+  var rev1 = parts[0]
+  var rev2 = parts[1]
+  if (!/[0-9a-f]{24}/.test(rev1)) return pull(
+    ph('div.error', 'rev 1 is not a git object id'),
+    self.wrapPage('git diff'),
+    self.respondSink(400)
+  )
+  if (!/[0-9a-f]{24}/.test(rev2)) return pull(
+    ph('div.error', 'rev 2 is not a git object id'),
+    self.wrapPage('git diff'),
+    self.respondSink(400)
+  )
+
+  if (!u.isRef(self.query.msg)) return pull(
+    ph('div.error', 'missing message id'),
+    self.wrapPage('git diff'),
+    self.respondSink(400)
+  )
+
+  var done = multicb({pluck: 1, spread: true})
+  // the msg qs param should point to the message for rev2 object. the msg for
+  // rev1 object we will have to look up.
+  self.app.git.getObjectMsg({
+    obj: rev1,
+    headMsgId: self.query.msg,
+    type: 'blob',
+  }, done())
+  self.getMsgDecryptedMaybeOoo(self.query.msg, done())
+  done(function (err, msg1, msg2) {
+    if (err) return pull(
+      pull.once(u.renderError(err).outerHTML),
+      self.wrapPage('git diff ' + revs),
+      self.respondSink(400)
+    )
+    var msg1Date = new Date(msg1.value.timestamp)
+    var msg2Date = new Date(msg2.value.timestamp)
+    var revsShort = rev1.substr(0, 8) + '..' + rev2.substr(0, 8)
+    pull(
+      ph('section', [
+        ph('h3', ph('a', {href: ''}, revsShort)),
+        ph('div', [
+          ph('a', {
+            href: self.app.render.toUrl('/git/blob/' + rev1 + '?msg=' + encodeURIComponent(msg1.key))
+          }, rev1), ' ',
+          self.phIdLink(msg1.value.author), ' ',
+          ph('a', {
+            href: self.app.render.toUrl(msg1.key),
+            title: msg1Date.toLocaleString(),
+          }, htime(msg1Date))
+        ]),
+        ph('div', [
+          ph('a', {
+            href: self.app.render.toUrl('/git/blob/' + rev2 + '?msg=' + encodeURIComponent(msg2.key))
+          }, rev2), ' ',
+          self.phIdLink(msg2.value.author), ' ',
+          ph('a', {
+            href: self.app.render.toUrl(msg2.key),
+            title: msg2Date.toLocaleString(),
+          }, htime(msg2Date))
+        ]),
+        u.readNext(function (cb) {
+          var done = multicb({pluck: 1, spread: true})
+          self.app.git.openObject({
+            obj: rev1,
+            msg: msg1.key,
+          }, done())
+          self.app.git.openObject({
+            obj: rev2,
+            msg: msg2.key,
+          }, done())
+          done(function (err, obj1, obj2) {
+            if (err && err.name === 'BlobNotFoundError')
+              return cb(null, self.askWantBlobsForm(err.links))
+            if (err) return cb(err)
+
+            var done = multicb({pluck: 1, spread: true})
+            pull.collect(done())(self.app.git.readObject(obj1))
+            pull.collect(done())(self.app.git.readObject(obj2))
+            done(function (err, bufs1, bufs2) {
+              if (err) return cb(err)
+              var str1 = Buffer.concat(bufs1, obj1.length).toString('utf8')
+              var str2 = Buffer.concat(bufs2, obj2.length).toString('utf8')
+              var diff = Diff.structuredPatch('', '', str1, str2)
+              cb(null, self.gitDiffTable(diff))
+            })
+          })
+        })
+      ]),
+      self.wrapPage('git diff'),
+      self.respondSink(200)
+    )
+  })
+}
+
+Serve.prototype.gitDiffTable = function (diff) {
+  var self = this
+  return pull(
+    ph('table', [
+      ph('tr', [
+      ]),
+      pull(
+        pull.values(diff.hunks),
+        pull.map(function (hunk) {
+          var oldLine = hunk.oldStart
+          var newLine = hunk.newStart
+          return [
+            ph('tr', [
+              ph('td', {colspan: 2}),
+              ph('td', ph('pre',
+                '@@ -' + oldLine + ',' + hunk.oldLines + ' ' +
+                '+' + newLine + ',' + hunk.newLines + ' @@'))
+            ]),
+            pull(
+              pull.values(hunk.lines),
+              pull.map(function (line) {
+                var s = line[0]
+                if (s == '\\') return
+                var html = self.app.render.highlight(line)
+                var lineNums = [s == '+' ? '' : oldLine++, s == '-' ? '' : newLine++]
+                // var id = [filename].concat(lineNums).join('-')
+                var newLineNum = lineNums[lineNums.length-1]
+                return ph('tr', {
+                  class: s == '+' ? 'diff-new' : s == '-' ? 'diff-old' : ''
+                }, [
+                  lineNums.map(function (num, i) {
+                    return ph('td', String(num))
+                    // TODO: allow linking to comments
+                    /*
+                      var idEnc = encodeURIComponent(id)
+                      return '<td class="code-linenum">' +
+                        (num ? '<a href="#' + idEnc + '">' +
+                          num + '</a>' +
+                          (updateId && i === lineNums.length-1 && s !== '-' ?
+                            ' <a href="?comment=' + idEnc + '#' + idEnc + '">…</a>'
+                          : '')
+                        : '') + '</td>'
+                    }
+                    */
+                  }),
+                  ph('td', ph('pre', u.escapeHTML(html)))
+                ])
+
+                // TODO: line-comments
+                /*
+                  (lineCommentThreads[newLineNum] ?
+                    '<tr><td colspan=4>' +
+                      lineCommentThreads[newLineNum] +
+                    '</td></tr>'
+                  : commit && query.comment === id ?
+                    '<tr><td colspan=4>' +
+                      forms.lineComment(req, repo, updateId, commit, filename, newLineNum) +
+                    '</td></tr>'
+                  : '')
+                  */
+              })
+            )
+          ]
+        })
+      )
+    ])
+  )
+}
+
 Serve.prototype.gitObjectLinks = function (headMsgId, type) {
   var self = this
   return paramap(function (id, cb) {
diff --git a/package-lock.json b/package-lock.json
index 8d381d4..3a9bf62 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -180,6 +180,10 @@
         "streamsearch": "0.1.2"
       }
     },
+    "diff": {
+      "version": "3.3.1",
+      "resolved": "http://localhost:8989/blobs/get/&+6G9mvp4Q/5bujMKlbFdbrub2IXMPleXIqTqyyvY5Ww=.sha256"
+    },
     "ed2curve": {
       "version": "0.1.4",
       "resolved": "http://localhost:8989/blobs/get/&X6VtEiGqSVFiIHAZAXFZXB5q9iUd3gULIU9c0xyynNo=.sha256",
diff --git a/package.json b/package.json
index 62ec8d9..65ae820 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
     "asyncmemo": "^1.1.0",
     "base64-url": "^2.0.0",
     "busboy": "^0.2.14",
+    "diff": "^3.3.1",
     "emoji-named-characters": "^1.0.2",
     "emoji-server": "^1.0.0",
     "hashlru": "^2.1.0",
diff --git a/static/styles.css b/static/styles.css
index c26cf59..b22074f 100644
--- a/static/styles.css
+++ b/static/styles.css
@@ -193,3 +193,6 @@ table.ssb-object td {
 .chess-square-dark {
   background-color: #ccc;
 }
+
+.diff-old { background-color: #ffe2dd; }
+.diff-new { background-color: #d1ffd6; }