Blob api (#132)

* Add repo_blob

This adds a new Repository.GetBlob(id) method for use by gitea.

* This is a follow-up for PR #121 to implement blob_api including full test coverage

Signed-off-by: Berengar W. Lehr <Berengar.Lehr@kompetenztest.de>

repo_blob.go

@@ -0,0 +1,30 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+func (repo *Repository) getBlob(id SHA1) (*Blob, error) {
+	if _, err := NewCommand("cat-file", "-p", id.String()).RunInDir(repo.Path); err != nil {
+		return nil, ErrNotExist{id.String(), ""}
+	}
+
+	return &Blob{
+		repo: repo,
+		TreeEntry: &TreeEntry{
+			ID: id,
+			ptree: &Tree{
+				repo: repo,
+			},
+		},
+	}, nil
+}
+
+// GetBlob finds the blob object in the repository.
+func (repo *Repository) GetBlob(idStr string) (*Blob, error) {
+	id, err := NewIDFromString(idStr)
+	if err != nil {
+		return nil, err
+	}
+	return repo.getBlob(id)
+}

repo_blob_test.go

@@ -0,0 +1,66 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRepository_GetBlob_Found(t *testing.T) {
+	repoPath := filepath.Join(testReposDir, "repo1_bare")
+	r, err := OpenRepository(repoPath)
+	assert.NoError(t, err)
+
+	testCases := []struct {
+		OID  string
+		Data []byte
+	}{
+		{"e2129701f1a4d54dc44f03c93bca0a2aec7c5449", []byte("file1\n")},
+		{"6c493ff740f9380390d5c9ddef4af18697ac9375", []byte("file2\n")},
+	}
+
+	for _, testCase := range testCases {
+		blob, err := r.GetBlob(testCase.OID)
+		assert.NoError(t, err)
+
+		dataReader, err := blob.Data()
+		assert.NoError(t, err)
+
+		data, err := ioutil.ReadAll(dataReader)
+		assert.NoError(t, err)
+		assert.Equal(t, testCase.Data, data)
+	}
+}
+
+func TestRepository_GetBlob_NotExist(t *testing.T) {
+	repoPath := filepath.Join(testReposDir, "repo1_bare")
+	r, err := OpenRepository(repoPath)
+	assert.NoError(t, err)
+
+	testCase := "0000000000000000000000000000000000000000"
+	testError := ErrNotExist{testCase, ""}
+
+	blob, err := r.GetBlob(testCase)
+	assert.Nil(t, blob)
+	assert.EqualError(t, err, testError.Error())
+}
+
+func TestRepository_GetBlob_NoId(t *testing.T) {
+	repoPath := filepath.Join(testReposDir, "repo1_bare")
+	r, err := OpenRepository(repoPath)
+	assert.NoError(t, err)
+
+	testCase := ""
+	testError := fmt.Errorf("Length must be 40: %s", testCase)
+
+	blob, err := r.GetBlob(testCase)
+	assert.Nil(t, blob)
+	assert.EqualError(t, err, testError.Error())
+}