From 3a0cf82a5d967957a21f5fb0164107e17a494015 Mon Sep 17 00:00:00 2001
From: Michael Runge <mrunge@google.com>
Date: Wed, 6 Nov 2013 17:42:20 -0800
Subject: Enable incremental builder to find files that moved, and try to
 process them via patch + rename, instead of delete + add.

b/11437930

Change-Id: I984349fbc9a8dac4379e00c0d66fc7d22c4eb834
---
 updater/install.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/updater/install.c b/updater/install.c
index ff4dd5829..48791ede9 100644
--- a/updater/install.c
+++ b/updater/install.c
@@ -286,6 +286,40 @@ done:
     return StringValue(result);
 }
 
+Value* RenameFn(const char* name, State* state, int argc, Expr* argv[]) {
+    char* result = NULL;
+    if (argc != 2) {
+        return ErrorAbort(state, "%s() expects 2 args, got %d", name, argc);
+    }
+
+    char* src_name;
+    char* dst_name;
+
+    if (ReadArgs(state, argv, 2, &src_name, &dst_name) < 0) {
+        return NULL;
+    }
+    if (strlen(src_name) == 0) {
+        ErrorAbort(state, "src_name argument to %s() can't be empty", name);
+        goto done;
+    }
+    if (strlen(dst_name) == 0) {
+        ErrorAbort(state, "dst_name argument to %s() can't be empty",
+                   name);
+        goto done;
+    }
+
+    if (rename(src_name, dst_name) != 0) {
+        ErrorAbort(state, "Rename of %s() to %s() failed, error %s()",
+          src_name, dst_name, strerror(errno));
+    } else {
+        result = dst_name;
+    }
+
+done:
+    free(src_name);
+    if (result != dst_name) free(dst_name);
+    return StringValue(result);
+}
 
 Value* DeleteFn(const char* name, State* state, int argc, Expr* argv[]) {
     char** paths = malloc(argc * sizeof(char*));
@@ -1374,6 +1408,7 @@ void RegisterInstallFunctions() {
 
     RegisterFunction("read_file", ReadFileFn);
     RegisterFunction("sha1_check", Sha1CheckFn);
+    RegisterFunction("rename", RenameFn);
 
     RegisterFunction("wipe_cache", WipeCacheFn);
 
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