Refactor "Content" for file uploading (#25851)

Before: the concept "Content string" is used everywhere. It has some
problems:

1. Sometimes it means "base64 encoded content", sometimes it means "raw
binary content"
2. It doesn't work with large files, eg: uploading a 1G LFS file would
make Gitea process OOM

This PR does the refactoring: use "ContentReader" / "ContentBase64"
instead of "Content"

This PR is not breaking because the key in API JSON is still "content":
`` ContentBase64 string `json:"content"` ``

10 files changed, 42 insertions, 37 deletions

diff --git a/tests/integration/actions_trigger_test.go b/tests/integration/actions_trigger_test.go
index bacf13e6c5..241d6172f7 100644
--- a/tests/integration/actions_trigger_test.go
+++ b/tests/integration/actions_trigger_test.go
@@ -5,6 +5,7 @@ package integration
 
 import (
 	"net/url"
+	"strings"
 	"testing"
 	"time"
 
@@ -64,9 +65,9 @@ func TestPullRequestTargetEvent(t *testing.T) {
 		addWorkflowToBaseResp, err := files_service.ChangeRepoFiles(git.DefaultContext, baseRepo, user2, &files_service.ChangeRepoFilesOptions{
 			Files: []*files_service.ChangeRepoFile{
 				{
-					Operation: "create",
-					TreePath:  ".gitea/workflows/pr.yml",
-					Content:   "name: test\non: pull_request_target\njobs:\n  test:\n    runs-on: ubuntu-latest\n    steps:\n      - run: echo helloworld\n",
+					Operation:     "create",
+					TreePath:      ".gitea/workflows/pr.yml",
+					ContentReader: strings.NewReader("name: test\non: pull_request_target\njobs:\n  test:\n    runs-on: ubuntu-latest\n    steps:\n      - run: echo helloworld\n"),
 				},
 			},
 			Message:   "add workflow",
@@ -92,9 +93,9 @@ func TestPullRequestTargetEvent(t *testing.T) {
 		addFileToForkedResp, err := files_service.ChangeRepoFiles(git.DefaultContext, forkedRepo, user3, &files_service.ChangeRepoFilesOptions{
 			Files: []*files_service.ChangeRepoFile{
 				{
-					Operation: "create",
-					TreePath:  "file_1.txt",
-					Content:   "file1",
+					Operation:     "create",
+					TreePath:      "file_1.txt",
+					ContentReader: strings.NewReader("file1"),
 				},
 			},
 			Message:   "add file1",
diff --git a/tests/integration/api_repo_file_create_test.go b/tests/integration/api_repo_file_create_test.go
index cbc164891b..2433a68c31 100644
--- a/tests/integration/api_repo_file_create_test.go
+++ b/tests/integration/api_repo_file_create_test.go
@@ -46,7 +46,7 @@ func getCreateFileOptions() api.CreateFileOptions {
 				Committer: time.Unix(978307190, 0),
 			},
 		},
-		Content: contentEncoded,
+		ContentBase64: contentEncoded,
 	}
 }
 
diff --git a/tests/integration/api_repo_file_helpers.go b/tests/integration/api_repo_file_helpers.go
index 8e9b2bfecc..27e127fcc8 100644
--- a/tests/integration/api_repo_file_helpers.go
+++ b/tests/integration/api_repo_file_helpers.go
@@ -4,6 +4,8 @@
 package integration
 
 import (
+	"strings"
+
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/git"
@@ -15,9 +17,9 @@ func createFileInBranch(user *user_model.User, repo *repo_model.Repository, tree
 	opts := &files_service.ChangeRepoFilesOptions{
 		Files: []*files_service.ChangeRepoFile{
 			{
-				Operation: "create",
-				TreePath:  treePath,
-				Content:   content,
+				Operation:     "create",
+				TreePath:      treePath,
+				ContentReader: strings.NewReader(content),
 			},
 		},
 		OldBranch: branchName,
diff --git a/tests/integration/api_repo_file_update_test.go b/tests/integration/api_repo_file_update_test.go
index 5bcb531fc1..9a29ccbf5e 100644
--- a/tests/integration/api_repo_file_update_test.go
+++ b/tests/integration/api_repo_file_update_test.go
@@ -44,7 +44,7 @@ func getUpdateFileOptions() *api.UpdateFileOptions {
 			},
 			SHA: "103ff9234cefeee5ec5361d22b49fbb04d385885",
 		},
-		Content: contentEncoded,
+		ContentBase64: contentEncoded,
 	}
 }
 
diff --git a/tests/integration/api_repo_files_change_test.go b/tests/integration/api_repo_files_change_test.go
index 8599b12a7f..c79764a067 100644
--- a/tests/integration/api_repo_files_change_test.go
+++ b/tests/integration/api_repo_files_change_test.go
@@ -44,13 +44,13 @@ func getChangeFilesOptions() *api.ChangeFilesOptions {
 		},
 		Files: []*api.ChangeFileOperation{
 			{
-				Operation: "create",
-				Content:   newContentEncoded,
+				Operation:     "create",
+				ContentBase64: newContentEncoded,
 			},
 			{
-				Operation: "update",
-				Content:   updateContentEncoded,
-				SHA:       "103ff9234cefeee5ec5361d22b49fbb04d385885",
+				Operation:     "update",
+				ContentBase64: updateContentEncoded,
+				SHA:           "103ff9234cefeee5ec5361d22b49fbb04d385885",
 			},
 			{
 				Operation: "delete",
diff --git a/tests/integration/empty_repo_test.go b/tests/integration/empty_repo_test.go
index d604391dab..78453f28a5 100644
--- a/tests/integration/empty_repo_test.go
+++ b/tests/integration/empty_repo_test.go
@@ -125,7 +125,7 @@ func TestEmptyRepoAddFileByAPI(t *testing.T) {
 			NewBranchName: "new_branch",
 			Message:       "init",
 		},
-		Content: base64.StdEncoding.EncodeToString([]byte("newly-added-api-file")),
+		ContentBase64: base64.StdEncoding.EncodeToString([]byte("newly-added-api-file")),
 	})
 
 	resp := MakeRequest(t, req, http.StatusCreated)
diff --git a/tests/integration/gpg_git_test.go b/tests/integration/gpg_git_test.go
index 5b49c91c59..10174b99fe 100644
--- a/tests/integration/gpg_git_test.go
+++ b/tests/integration/gpg_git_test.go
@@ -337,7 +337,7 @@ func crudActionCreateFile(t *testing.T, ctx APITestContext, user *user_model.Use
 				Email: user.Email,
 			},
 		},
-		Content: base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("This is new text for %s", path))),
+		ContentBase64: base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("This is new text for %s", path))),
 	}, callback...)
 }
 
diff --git a/tests/integration/pull_merge_test.go b/tests/integration/pull_merge_test.go
index 7b7c8864c7..f958c890fe 100644
--- a/tests/integration/pull_merge_test.go
+++ b/tests/integration/pull_merge_test.go
@@ -370,9 +370,9 @@ func TestConflictChecking(t *testing.T) {
 		_, err = files_service.ChangeRepoFiles(git.DefaultContext, baseRepo, user, &files_service.ChangeRepoFilesOptions{
 			Files: []*files_service.ChangeRepoFile{
 				{
-					Operation: "create",
-					TreePath:  "important_file",
-					Content:   "Just a non-important file",
+					Operation:     "create",
+					TreePath:      "important_file",
+					ContentReader: strings.NewReader("Just a non-important file"),
 				},
 			},
 			Message:   "Add a important file",
@@ -385,9 +385,9 @@ func TestConflictChecking(t *testing.T) {
 		_, err = files_service.ChangeRepoFiles(git.DefaultContext, baseRepo, user, &files_service.ChangeRepoFilesOptions{
 			Files: []*files_service.ChangeRepoFile{
 				{
-					Operation: "create",
-					TreePath:  "important_file",
-					Content:   "Not the same content :P",
+					Operation:     "create",
+					TreePath:      "important_file",
+					ContentReader: strings.NewReader("Not the same content :P"),
 				},
 			},
 			Message:   "Add a important file",
diff --git a/tests/integration/pull_update_test.go b/tests/integration/pull_update_test.go
index fa56cec485..80c55042db 100644
--- a/tests/integration/pull_update_test.go
+++ b/tests/integration/pull_update_test.go
@@ -6,6 +6,7 @@ package integration
 import (
 	"net/http"
 	"net/url"
+	"strings"
 	"testing"
 	"time"
 
@@ -104,9 +105,9 @@ func createOutdatedPR(t *testing.T, actor, forkOrg *user_model.User) *issues_mod
 	_, err = files_service.ChangeRepoFiles(git.DefaultContext, baseRepo, actor, &files_service.ChangeRepoFilesOptions{
 		Files: []*files_service.ChangeRepoFile{
 			{
-				Operation: "create",
-				TreePath:  "File_A",
-				Content:   "File A",
+				Operation:     "create",
+				TreePath:      "File_A",
+				ContentReader: strings.NewReader("File A"),
 			},
 		},
 		Message:   "Add File A",
@@ -131,9 +132,9 @@ func createOutdatedPR(t *testing.T, actor, forkOrg *user_model.User) *issues_mod
 	_, err = files_service.ChangeRepoFiles(git.DefaultContext, headRepo, actor, &files_service.ChangeRepoFilesOptions{
 		Files: []*files_service.ChangeRepoFile{
 			{
-				Operation: "create",
-				TreePath:  "File_B",
-				Content:   "File B",
+				Operation:     "create",
+				TreePath:      "File_B",
+				ContentReader: strings.NewReader("File B"),
 			},
 		},
 		Message:   "Add File on PR branch",
diff --git a/tests/integration/repofiles_change_test.go b/tests/integration/repofiles_change_test.go
index c273d38188..765a44689a 100644
--- a/tests/integration/repofiles_change_test.go
+++ b/tests/integration/repofiles_change_test.go
@@ -6,6 +6,7 @@ package integration
 import (
 	"net/url"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
@@ -24,9 +25,9 @@ func getCreateRepoFilesOptions(repo *repo_model.Repository) *files_service.Chang
 	return &files_service.ChangeRepoFilesOptions{
 		Files: []*files_service.ChangeRepoFile{
 			{
-				Operation: "create",
-				TreePath:  "new/file.txt",
-				Content:   "This is a NEW file",
+				Operation:     "create",
+				TreePath:      "new/file.txt",
+				ContentReader: strings.NewReader("This is a NEW file"),
 			},
 		},
 		OldBranch: repo.DefaultBranch,
@@ -41,10 +42,10 @@ func getUpdateRepoFilesOptions(repo *repo_model.Repository) *files_service.Chang
 	return &files_service.ChangeRepoFilesOptions{
 		Files: []*files_service.ChangeRepoFile{
 			{
-				Operation: "update",
-				TreePath:  "README.md",
-				SHA:       "4b4851ad51df6a7d9f25c979345979eaeb5b349f",
-				Content:   "This is UPDATED content for the README file",
+				Operation:     "update",
+				TreePath:      "README.md",
+				SHA:           "4b4851ad51df6a7d9f25c979345979eaeb5b349f",
+				ContentReader: strings.NewReader("This is UPDATED content for the README file"),
 			},
 		},
 		OldBranch: repo.DefaultBranch,