refactor: Move pruning/reindex/importing globals to blockstorage

Can be reviewed with --color-moved=dimmed-zebra

src/node/blockstorage.cpp

@@ -15,6 +15,58 @@
 #include <util/system.h>
 #include <validation.h>
 
+std::atomic_bool fImporting(false);
+std::atomic_bool fReindex(false);
+bool fHavePruned = false;
+bool fPruneMode = false;
+uint64_t nPruneTarget = 0;
+
+bool IsBlockPruned(const CBlockIndex* pblockindex)
+{
+    return (fHavePruned && !(pblockindex->nStatus & BLOCK_HAVE_DATA) && pblockindex->nTx > 0);
+}
+
+// If we're using -prune with -reindex, then delete block files that will be ignored by the
+// reindex.  Since reindexing works by starting at block file 0 and looping until a blockfile
+// is missing, do the same here to delete any later block files after a gap.  Also delete all
+// rev files since they'll be rewritten by the reindex anyway.  This ensures that vinfoBlockFile
+// is in sync with what's actually on disk by the time we start downloading, so that pruning
+// works correctly.
+void CleanupBlockRevFiles()
+{
+    std::map<std::string, fs::path> mapBlockFiles;
+
+    // Glob all blk?????.dat and rev?????.dat files from the blocks directory.
+    // Remove the rev files immediately and insert the blk file paths into an
+    // ordered map keyed by block file index.
+    LogPrintf("Removing unusable blk?????.dat and rev?????.dat files for -reindex with -prune\n");
+    fs::path blocksdir = gArgs.GetBlocksDirPath();
+    for (fs::directory_iterator it(blocksdir); it != fs::directory_iterator(); it++) {
+        if (fs::is_regular_file(*it) &&
+            it->path().filename().string().length() == 12 &&
+            it->path().filename().string().substr(8,4) == ".dat")
+        {
+            if (it->path().filename().string().substr(0,3) == "blk")
+                mapBlockFiles[it->path().filename().string().substr(3,5)] = it->path();
+            else if (it->path().filename().string().substr(0,3) == "rev")
+                remove(it->path());
+        }
+    }
+
+    // Remove all block files that aren't part of a contiguous set starting at
+    // zero by walking the ordered map (keys are block file indices) by
+    // keeping a separate counter.  Once we hit a gap (or if 0 doesn't exist)
+    // start removing block files.
+    int nContigCounter = 0;
+    for (const std::pair<const std::string, fs::path>& item : mapBlockFiles) {
+        if (atoi(item.first) == nContigCounter) {
+            nContigCounter++;
+            continue;
+        }
+        remove(item.second);
+    }
+}
+
 // From validation. TODO move here
 bool FindBlockPos(FlatFilePos& pos, unsigned int nAddSize, unsigned int nHeight, CChain& active_chain, uint64_t nTime, bool fKnown = false);