Revert of "[sql] Remove part of WebDatabase SQLite patch." (patchset #1 of https://codereview.chrom…

third_party/sqlite/src/src/os_unix.c

Index: third_party/sqlite/src/src/os_unix.c
diff --git a/third_party/sqlite/src/src/os_unix.c b/third_party/sqlite/src/src/os_unix.c
index dc34066aeae65febc2c121069988582fea4be891..eaa97cf3595342ab82e3c69ab22fcd48af153e2b 100644
--- a/third_party/sqlite/src/src/os_unix.c
+++ b/third_party/sqlite/src/src/os_unix.c
@@ -5644,6 +5644,36 @@ int chromium_sqlite3_fill_in_unix_sqlite3_file(sqlite3_vfs* vfs,
 }
 
 /*
+** Search for an unused file descriptor that was opened on the database file.
+** If a suitable file descriptor if found, then it is stored in *fd; otherwise,
+** *fd is not modified.
+**
+** If a reusable file descriptor is not found, and a new UnixUnusedFd cannot
+** be allocated, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK is returned.
+*/
+CHROMIUM_SQLITE_API
+int chromium_sqlite3_get_reusable_file_handle(sqlite3_file* file,
+                                              const char* fileName,
+                                              int flags,
+                                              int* fd) {
+  unixFile* unixSQLite3File = (unixFile*)file;
+  int fileType = flags & 0xFFFFFF00;
+  if (fileType == SQLITE_OPEN_MAIN_DB) {
+    UnixUnusedFd *unusedFd = findReusableFd(fileName, flags);
+    if (unusedFd) {
+      *fd = unusedFd->fd;
+    } else {
+      unusedFd = sqlite3_malloc(sizeof(*unusedFd));
+      if (!unusedFd) {
+        return SQLITE_NOMEM;
+      }
+    }
+    unixSQLite3File->pUnused = unusedFd;
+  }
+  return SQLITE_OK;
+}
+
+/*
 ** Marks 'fd' as the unused file descriptor for 'pFile'.
 */
 CHROMIUM_SQLITE_API
@@ -5770,17 +5800,10 @@ static int unixOpen(
   chromium_sqlite3_initialize_unix_sqlite3_file(pFile);
 
   if( eType==SQLITE_OPEN_MAIN_DB ){
-    UnixUnusedFd *pUnused;
-    pUnused = findReusableFd(zName, flags);
-    if( pUnused ){
-      fd = pUnused->fd;
-    }else{
-      pUnused = sqlite3_malloc(sizeof(*pUnused));
-      if( !pUnused ){
-        return SQLITE_NOMEM;
-      }
+    rc = chromium_sqlite3_get_reusable_file_handle(pFile, zName, flags, &fd);
+    if( rc!=SQLITE_OK ){
+      return rc;
     }
-    p->pUnused = pUnused;
 
     /* Database filenames are double-zero terminated if they are not
     ** URIs with parameters.  Hence, they can always be passed into