Implement file history walk in revwalk

examples/walk-history-for-file.js

@@ -1,49 +1,62 @@
 var nodegit = require("../"),
-    path = require("path");
+    path = require("path"),
+    historyFile = "generate/input/descriptor.json",
+    walker,
+    historyCommits = [],
+    commit,
+    repo;
 
 // This code walks the history of the master branch and prints results
 // that look very similar to calling `git log` from the command line
 
+function compileHistory(resultingArrayOfCommits) {
+  var lastSha;
+  if (historyCommits.length > 0) {
+    lastSha = historyCommits[historyCommits.length - 1].commit.sha();
+    if (
+      resultingArrayOfCommits.length == 1 &&
+      resultingArrayOfCommits[0].commit.sha() == lastSha
+    ) {
+      return;
+    }
+  }
+
+  resultingArrayOfCommits.forEach(function(entry) {
+    historyCommits.push(entry);
+  });
+
+  lastSha = historyCommits[historyCommits.length - 1].commit.sha();
+
+  walker = repo.createRevWalk();
+  walker.push(lastSha);
+  walker.sorting(nodegit.Revwalk.SORT.TIME);
+
+  return walker.fileHistoryWalk(historyFile, 500)
+    .then(compileHistory);
+}
+
 nodegit.Repository.open(path.resolve(__dirname, "../.git"))
-  .then(function(repo) {
+  .then(function(r) {
+    repo = r;
     return repo.getMasterCommit();
   })
   .then(function(firstCommitOnMaster){
     // History returns an event.
-    var history = firstCommitOnMaster.history(nodegit.Revwalk.SORT.Time);
-    var commits = [];
-
-    // History emits "commit" event for each commit in the branch's history
-    history.on("commit", function(commit) {
-      return commit.getDiff()
-      .then(function(diffList) {
-        diffList.map(function(diff) {
-          diff.patches().then(function(patches) {
-            patches.map(function(patch) {
-              var result =
-                !!~patch.oldFile().path().indexOf("descriptor.json") ||
-                !!~patch.newFile().path().indexOf("descriptor.json");
-
-              if(result && !~commits.indexOf(commit)) {
-                commits.push(commit);
-              }
-            });
-          });
-        });
-      });
-    });
+    walker = repo.createRevWalk();
+    walker.push(firstCommitOnMaster.sha());
+    walker.sorting(nodegit.Revwalk.SORT.Time);
 
-    history.on("end", function() {
-      commits.forEach(function(commit) {
-        console.log("commit " + commit.sha());
-        console.log("Author:", commit.author().name() +
-          " <" + commit.author().email() + ">");
-        console.log("Date:", commit.date());
-        console.log("\n    " + commit.message());
-      });
+    return walker.fileHistoryWalk(historyFile, 500);
+  })
+  .then(compileHistory)
+  .then(function() {
+    historyCommits.forEach(function(entry) {
+      commit = entry.commit;
+      console.log("commit " + commit.sha());
+      console.log("Author:", commit.author().name() +
+        " <" + commit.author().email() + ">");
+      console.log("Date:", commit.date());
+      console.log("\n    " + commit.message());
     });
-
-    // Don't forget to call `start()`!
-    history.start();
   })
   .done();

generate/input/descriptor.json

@@ -1857,6 +1857,10 @@
       "ignore": true
     },
     "revwalk": {
+      "dependencies": [
+        "../include/commit.h",
+        "../include/functions/copy.h"
+      ],
       "functions": {
         "git_revwalk_add_hide_cb": {
           "ignore": true

generate/input/libgit2-supplement.json

@@ -200,6 +200,36 @@
           "isErrorCode": true
         }
       },
+      "git_revwalk_file_history_walk": {
+        "args": [
+          {
+            "name": "file_path",
+            "type": "const char *"
+          },
+          {
+            "name": "max_count",
+            "type": "int"
+          },
+          {
+            "name": "out",
+            "type": "std::vector< std::pair<git_commit *, std::pair<char *, git_delta_t> > *> *"
+          },
+          {
+            "name": "walk",
+            "type": "git_revwalk *"
+          }
+        ],
+        "type": "function",
+        "isManual": true,
+        "cFile": "generate/templates/manual/revwalk/file_history_walk.cc",
+        "isAsync": true,
+        "isPrototypeMethod": true,
+        "group": "revwalk",
+        "return": {
+          "type": "int",
+          "isErrorCode": true
+        }
+      },
       "git_stash_save": {
         "type": "function",
         "file": "stash.h",
@@ -263,7 +293,8 @@
       [
         "revwalk",
         [
-          "git_revwalk_fast_walk"
+          "git_revwalk_fast_walk",
+          "git_revwalk_file_history_walk"
         ]
       ],
       [