Add KATI_file_no_rerun function

The syntax is the same as $(file), but it will only be run once.

Similar to $(KATI_shell_no_rerun), we want to generate files during
kati, but not regenerate them on every invocation of kati.

Test: unit tests pass
Change-Id: I34b7972a0a9f0540da322a995c30fef2efd16145

2 files changed, 80 insertions, 9 deletions

diff --git a/src/func.cc b/src/func.cc
index d5bca3a..912cee1 100644
--- a/src/func.cc
+++ b/src/func.cc
@@ -793,9 +793,10 @@ void ErrorFunc(const std::vector<Value*>& args, Evaluator* ev, std::string*) {
   ev->Error(StringPrintf("*** %s.", a.c_str()));
 }
 
-static void FileReadFunc(Evaluator* ev,
+static void FileReadFunc_(Evaluator* ev,
                          const std::string& filename,
-                         std::string* s) {
+                         std::string* s,
+                         bool rerun) {
   int fd = open(filename.c_str(), O_RDONLY);
   if (fd < 0) {
     if (errno == ENOENT) {
@@ -833,7 +834,7 @@ static void FileReadFunc(Evaluator* ev,
     out.pop_back();
   }
 
-  if (ShouldStoreCommandResult(filename)) {
+  if (rerun && ShouldStoreCommandResult(filename)) {
     CommandResult* cr = new CommandResult();
     cr->op = CommandOp::READ;
     cr->cmd = filename;
@@ -843,10 +844,11 @@ static void FileReadFunc(Evaluator* ev,
   *s += out;
 }
 
-static void FileWriteFunc(Evaluator* ev,
+static void FileWriteFunc_(Evaluator* ev,
                           const std::string& filename,
                           bool append,
-                          std::string text) {
+                          std::string text,
+                          bool rerun) {
   FILE* f = fopen(filename.c_str(), append ? "ab" : "wb");
   if (f == NULL) {
     ev->Error("*** fopen failed.");
@@ -860,7 +862,7 @@ static void FileWriteFunc(Evaluator* ev,
     ev->Error("*** fclose failed.");
   }
 
-  if (ShouldStoreCommandResult(filename)) {
+  if (rerun && ShouldStoreCommandResult(filename)) {
     CommandResult* cr = new CommandResult();
     cr->op = CommandOp::WRITE;
     cr->cmd = filename;
@@ -870,7 +872,7 @@ static void FileWriteFunc(Evaluator* ev,
   }
 }
 
-void FileFunc(const std::vector<Value*>& args, Evaluator* ev, std::string* s) {
+void FileFunc_(const std::vector<Value*>& args, Evaluator* ev, std::string* s, bool rerun) {
   if (ev->avoid_io()) {
     ev->Error("*** $(file ...) is not supported in rules.");
   }
@@ -891,7 +893,7 @@ void FileFunc(const std::vector<Value*>& args, Evaluator* ev, std::string* s) {
       ev->Error("*** invalid argument");
     }
 
-    FileReadFunc(ev, std::string(filename), s);
+    FileReadFunc_(ev, std::string(filename), s, rerun);
   } else if (filename[0] == '>') {
     bool append = false;
     if (filename[1] == '>') {
@@ -913,13 +915,21 @@ void FileFunc(const std::vector<Value*>& args, Evaluator* ev, std::string* s) {
       }
     }
 
-    FileWriteFunc(ev, std::string(filename), append, text);
+    FileWriteFunc_(ev, std::string(filename), append, text, rerun);
   } else {
     ev->Error(StringPrintf("*** Invalid file operation: %s.  Stop.",
                            std::string(filename).c_str()));
   }
 }
 
+void FileFunc(const std::vector<Value*>& args, Evaluator* ev, std::string* s) {
+  FileFunc_(args, ev, s, true);
+}
+
+void FileFuncNoRerun(const std::vector<Value*>& args, Evaluator* ev, std::string* s) {
+  FileFunc_(args, ev, s, false);
+}
+
 void DeprecatedVarFunc(const std::vector<Value*>& args,
                        Evaluator* ev,
                        std::string*) {
@@ -1131,6 +1141,7 @@ static const std::unordered_map<std::string_view, FuncInfo> g_func_info_map = {
     ENTRY("KATI_extra_file_deps", &ExtraFileDepsFunc, 0, 0, false, false),
     ENTRY("KATI_shell_no_rerun", &ShellFuncNoRerun, 1, 1, false, false),
     ENTRY("KATI_foreach_sep", &ForeachWithSepFunc, 4, 4, false, false),
+    ENTRY("KATI_file_no_rerun", &FileFuncNoRerun, 2, 1, false, false),
 };
 
 }  // namespace
diff --git a/testcase/ninja_file_no_rerun_func.sh b/testcase/ninja_file_no_rerun_func.sh
new file mode 100755
index 0000000..120432a
--- /dev/null
+++ b/testcase/ninja_file_no_rerun_func.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+#
+# Copyright 2023 Google Inc. All rights reserved
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http:#www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -e
+
+log=stderr_log
+mk="$@"
+
+echo "PASS" >testfile
+
+cat <<EOF > Makefile
+ifdef KATI
+SUPPORTS_FILE := 1
+endif
+ifneq (,\$(filter 4.2%,\$(MAKE_VERSION)))
+SUPPORTS_FILE := 1
+endif
+
+ifdef KATI
+  \$(KATI_file_no_rerun >testwrite,PASS)
+  RESULT := \$(KATI_file_no_rerun <testwrite)
+else
+ifdef SUPPORTS_FILE
+  \$(file >testwrite,PASS)
+  RESULT := \$(file <testwrite)
+else
+  # Make <4 does not support \$(file ...)
+  \$(info Read back: PASS)
+  RESULT := PASS
+endif
+endif
+
+all: ;@echo \$(RESULT)
+EOF
+
+${mk} 2> ${log}
+if [ -e ninja.sh ]; then
+  ./ninja.sh
+fi
+
+${mk} 2> ${log}
+if [ -e ninja.sh ]; then
+  if grep -q regenerating ${log}; then
+    echo 'Should not be regenerated'
+  fi
+  ./ninja.sh
+fi