Add apply-patch, basic revert and cherry-pick functionality (#17902)

This code adds a simple endpoint to apply patches to repositories and
branches on gitea. This is then used along with the conflicting checking
code in #18004 to provide a basic implementation of cherry-pick revert.

Now because the buttons necessary for cherry-pick and revert have 
required us to create a dropdown next to the Browse Source button
I've also implemented Create Branch and Create Tag operations.

Fix #3880 
Fix #17986 

Signed-off-by: Andrew Thornton <art27@cantab.net>

2 files changed, 91 insertions, 0 deletions

diff --git a/templates/repo/editor/cherry_pick.tmpl b/templates/repo/editor/cherry_pick.tmpl
new file mode 100644
index 0000000000..9cdda2ea83
--- /dev/null
+++ b/templates/repo/editor/cherry_pick.tmpl
@@ -0,0 +1,32 @@
+{{template "base/head" .}}
+<div class="page-content repository file editor edit">
+	{{template "repo/header" .}}
+	<div class="ui container">
+		{{template "base/alert" .}}
+		<form class="ui edit form" method="post" action="{{.RepoLink}}/_cherrypick/{{.SHA}}/{{.BranchName  | PathEscapeSegments}}">
+			{{.CsrfTokenHtml}}
+			<input type="hidden" name="last_commit" value="{{.last_commit}}">
+			<input type="hidden" name="page_has_posted" value="true">
+			<input type="hidden" name="revert" value="{{if eq .CherryPickType "revert"}}true{{else}}false{{end}}">
+			<div class="ui secondary menu">
+				<div class="fitted item treepath">
+					<div class="ui breadcrumb field {{if .Err_TreePath}}error{{end}}">
+						{{$shaurl := printf "%s/commit/%s" $.RepoLink (PathEscape .SHA)}}
+						{{$shalink := printf "<a class=\"ui blue sha label\" href=\"%s\">%s</a>" (Escape $shaurl) (ShortSha .SHA)}}
+						{{if eq .CherryPickType "revert"}}
+							{{.i18n.Tr "repo.editor.revert" $shalink | Str2html}}
+						{{else}}
+							{{.i18n.Tr "repo.editor.cherry_pick" $shalink | Str2html}}
+						{{end}}
+						<a class="section" href="{{$.RepoLink}}">{{.Repository.FullName}}</a>
+						<div class="divider">:</div>
+						<a class="section" href="{{$.BranchLink}}">{{.BranchName}}</a>
+						<span>{{.i18n.Tr "repo.editor.or"}} <a href="{{$shaurl}}">{{.i18n.Tr "repo.editor.cancel_lower"}}</a></span>
+					</div>
+				</div>
+			</div>
+			{{template "repo/editor/commit_form" .}}
+		</form>
+	</div>
+</div>
+{{template "base/footer" .}}
diff --git a/templates/repo/editor/patch.tmpl b/templates/repo/editor/patch.tmpl
new file mode 100644
index 0000000000..cecda907a4
--- /dev/null
+++ b/templates/repo/editor/patch.tmpl
@@ -0,0 +1,59 @@
+{{template "base/head" .}}
+<div class="page-content repository file editor edit">
+	{{template "repo/header" .}}
+	<div class="ui container">
+		{{template "base/alert" .}}
+		<form class="ui edit form" method="post" action="{{.RepoLink}}/_diffpatch/{{.BranchName  | PathEscapeSegments}}">
+			{{.CsrfTokenHtml}}
+			<input type="hidden" name="last_commit" value="{{.last_commit}}">
+			<input type="hidden" name="page_has_posted" value="{{.PageHasPosted}}">
+			<div class="ui secondary menu">
+				<div class="fitted item treepath">
+					<div class="ui breadcrumb field {{if .Err_TreePath}}error{{end}}">
+						{{.i18n.Tr "repo.editor.patching"}}
+						<a class="section" href="{{$.RepoLink}}">{{.Repository.FullName}}</a>
+						<div class="divider">:</div>
+						<a class="section" href="{{$.BranchLink}}">{{.BranchName}}</a>
+						<span>{{.i18n.Tr "repo.editor.or"}} <a href="{{$.BranchLink}}">{{.i18n.Tr "repo.editor.cancel_lower"}}</a></span>
+						<input type="hidden" id="tree_path" name="tree_path" value="patch" required>
+						<input id="file-name" type="hidden" value="diff.patch">
+					</div>
+				</div>
+			</div>
+			<div class="field">
+				<div class="ui top attached tabular menu" data-write="write">
+					<a class="active item" data-tab="write">{{svg "octicon-code" 16 "mr-2"}}{{.i18n.Tr "repo.editor.new_patch"}}</a>
+				</div>
+				<div class="ui bottom attached active tab segment" data-tab="write">
+					<textarea id="edit_area" name="content" class="hide" data-id="repo-{{.Repository.Name}}-patch"
+						data-context="{{.RepoLink}}"
+						data-line-wrap-extensions="{{.LineWrapExtensions}}">
+{{.FileContent}}</textarea>
+					<div class="editor-loading is-loading"></div>
+				</div>
+			</div>
+			{{template "repo/editor/commit_form" .}}
+		</form>
+	</div>
+
+	<div class="ui small basic modal" id="edit-empty-content-modal">
+		<div class="ui icon header">
+			<i class="file icon"></i>
+			{{.i18n.Tr "repo.editor.commit_empty_file_header"}}
+		</div>
+		<div class="center content">
+			<p>{{.i18n.Tr "repo.editor.commit_empty_file_text"}}</p>
+		</div>
+		<div class="actions">
+			<div class="ui red basic cancel inverted button">
+				<i class="remove icon"></i>
+				{{.i18n.Tr "repo.editor.cancel"}}
+			</div>
+			<div class="ui green basic ok inverted button">
+				<i class="save icon"></i>
+				{{.i18n.Tr "repo.editor.commit_changes"}}
+			</div>
+		</div>
+	</div>
+</div>
+{{template "base/footer" .}}