nixpkgs/pkgs/applications/audio/audacity/0001-Use-a-different-approach-to-estimate-the-disk-space-.patch

From deeb435829d73524df851f6f4c2d4be552c99230 Mon Sep 17 00:00:00 2001
From: Dmitry Vedenko <dmitry@crsib.me>
Date: Fri, 1 Oct 2021 16:21:22 +0300
Subject: [PATCH] Use a different approach to estimate the disk space usage

New a approach is a bit less precise, but removes the requirement for the "private" SQLite3 table and allows Audacity to be built against system SQLite3.
---
 cmake-proxies/sqlite/CMakeLists.txt |   5 -
 src/DBConnection.h                  |   4 +-
 src/ProjectFileIO.cpp               | 269 +++++-----------------------
 3 files changed, 44 insertions(+), 234 deletions(-)

diff --git a/cmake-proxies/sqlite/CMakeLists.txt b/cmake-proxies/sqlite/CMakeLists.txt
index 63d70637c..d7b9b95ef 100644
--- a/cmake-proxies/sqlite/CMakeLists.txt
+++ b/cmake-proxies/sqlite/CMakeLists.txt
@@ -19,11 +19,6 @@ list( APPEND INCLUDES
 
 list( APPEND DEFINES
    PRIVATE
-      #
-      # We need the dbpage table for space calculations.
-      #
-      SQLITE_ENABLE_DBPAGE_VTAB=1
-
       # Can't be set after a WAL mode database is initialized, so change
       # the default here to ensure all project files get the same page 
       # size.
diff --git a/src/DBConnection.h b/src/DBConnection.h
index 16a7fc9d4..07d3af95e 100644
--- a/src/DBConnection.h
+++ b/src/DBConnection.h
@@ -75,8 +75,8 @@ public:
       LoadSampleBlock,
       InsertSampleBlock,
       DeleteSampleBlock,
-      GetRootPage,
-      GetDBPage
+      GetSampleBlockSize,
+      GetAllSampleBlocksSize
    };
    sqlite3_stmt *Prepare(enum StatementID id, const char *sql);
 
diff --git a/src/ProjectFileIO.cpp b/src/ProjectFileIO.cpp
index 3b3e2e1fd..c9bc45af4 100644
--- a/src/ProjectFileIO.cpp
+++ b/src/ProjectFileIO.cpp
@@ -35,6 +35,7 @@ Paul Licameli split from AudacityProject.cpp
 #include "widgets/ProgressDialog.h"
 #include "wxFileNameWrapper.h"
 #include "xml/XMLFileReader.h"
+#include "MemoryX.h"`
 
 #undef NO_SHM
 #if !defined(__WXMSW__)
@@ -2357,255 +2358,69 @@ int64_t ProjectFileIO::GetTotalUsage()
 }
 
 //
-// Returns the amount of disk space used by the specified sample blockid or all
-// of the sample blocks if the blockid is 0.  It does this by using the raw SQLite
-// pages available from the "sqlite_dbpage" virtual table to traverse the SQLite
-// table b-tree described here:  https://www.sqlite.org/fileformat.html
+// Returns the estimation of disk space used by the specified sample blockid or all
+// of the sample blocks if the blockid is 0. This does not include small overhead
+// of the internal SQLite structures, only the size used by the data
 //
 int64_t ProjectFileIO::GetDiskUsage(DBConnection &conn, SampleBlockID blockid /* = 0 */)
 {
-   // Information we need to track our travels through the b-tree
-   typedef struct
-   {
-      int64_t pgno;
-      int currentCell;
-      int numCells;
-      unsigned char data[65536];
-   } page;
-   std::vector<page> stack;
-
-   int64_t total = 0;
-   int64_t found = 0;
-   int64_t right = 0;
-   int rc;
+   sqlite3_stmt* stmt = nullptr;
 
-   // Get the rootpage for the sampleblocks table.
-   sqlite3_stmt *stmt =
-      conn.Prepare(DBConnection::GetRootPage,
-                    "SELECT rootpage FROM sqlite_master WHERE tbl_name = 'sampleblocks';");
-   if (stmt == nullptr || sqlite3_step(stmt) != SQLITE_ROW)
+   if (blockid == 0)
    {
-      return 0;
-   }
-
-   // And store it in our first stack frame
-   stack.push_back({sqlite3_column_int64(stmt, 0)});
+      static const char* statement =
+R"(SELECT 
+	sum(length(blockid) + length(sampleformat) + 
+	length(summin) + length(summax) + length(sumrms) + 
+	length(summary256) + length(summary64k) +
+	length(samples))
+FROM sampleblocks;)";
 
-   // All done with the statement
-   sqlite3_clear_bindings(stmt);
-   sqlite3_reset(stmt);
-
-   // Prepare/retrieve statement to read raw database page
-   stmt = conn.Prepare(DBConnection::GetDBPage,
-      "SELECT data FROM sqlite_dbpage WHERE pgno = ?1;");
-   if (stmt == nullptr)
-   {
-      return 0;
+      stmt = conn.Prepare(DBConnection::GetAllSampleBlocksSize, statement);
    }
-
-   // Traverse the b-tree until we've visited all of the leaf pages or until
-   // we find the one corresponding to the passed in sample blockid. Because we
-   // use an integer primary key for the sampleblocks table, the traversal will
-   // be in ascending blockid sequence.
-   do
+   else
    {
-      // Acces the top stack frame
-      page &pg = stack.back();
+      static const char* statement =
+R"(SELECT 
+	length(blockid) + length(sampleformat) + 
+	length(summin) + length(summax) + length(sumrms) + 
+	length(summary256) + length(summary64k) +
+	length(samples)
+FROM sampleblocks WHERE blockid = ?1;)";
 
-      // Read the page from the sqlite_dbpage table if it hasn't yet been loaded
-      if (pg.numCells == 0)
-      {
-         // Bind the page number
-         sqlite3_bind_int64(stmt, 1, pg.pgno);
+      stmt = conn.Prepare(DBConnection::GetSampleBlockSize, statement);
+   }
 
-         // And retrieve the page
-         if (sqlite3_step(stmt) != SQLITE_ROW)
+   auto cleanup = finally(
+      [stmt]() {
+         // Clear statement bindings and rewind statement
+         if (stmt != nullptr)
          {
-            // REVIEW: Likely harmless failure - says size is zero on
-            // this error.
-            // LLL: Yea, but not much else we can do.
-            return 0;
+            sqlite3_clear_bindings(stmt);
+            sqlite3_reset(stmt);
          }
+      });
 
-         // Copy the page content to the stack frame
-         memcpy(&pg.data,
-                sqlite3_column_blob(stmt, 0),
-                sqlite3_column_bytes(stmt, 0));
-
-         // And retrieve the total number of cells within it
-         pg.numCells = get2(&pg.data[3]);
-
-         // Reset statement for next usage
-         sqlite3_clear_bindings(stmt);
-         sqlite3_reset(stmt);
-      }
-
-      //wxLogDebug("%*.*spgno %lld currentCell %d numCells %d", (stack.size() - 1) * 2, (stack.size() - 1) * 2, "", pg.pgno, pg.currentCell, pg.numCells);
-
-      // Process an interior table b-tree page
-      if (pg.data[0] == 0x05)
-      {
-         // Process the next cell if we haven't examined all of them yet
-         if (pg.currentCell < pg.numCells)
-         {
-            // Remember the right-most leaf page number.
-            right = get4(&pg.data[8]);
-
-            // Iterate over the cells.
-            //
-            // If we're not looking for a specific blockid, then we always push the
-            // target page onto the stack and leave the loop after a single iteration.
-            //
-            // Otherwise, we match the blockid against the highest integer key contained
-            // within the cell and if the blockid falls within the cell, we stack the
-            // page and stop the iteration.
-            //
-            // In theory, we could do a binary search for a specific blockid here, but
-            // because our sample blocks are always large, we will get very few cells
-            // per page...usually 6 or less.
-            //
-            // In both cases, the stacked page can be either an internal or leaf page.
-            bool stacked = false;
-            while (pg.currentCell < pg.numCells)
-            {
-               // Get the offset to this cell using the offset in the cell pointer
-               // array.
-               //
-               // The cell pointer array starts immediately after the page header
-               // at offset 12 and the retrieved offset is from the beginning of
-               // the page.
-               int celloff = get2(&pg.data[12 + (pg.currentCell * 2)]);
-
-               // Bump to the next cell for the next iteration.
-               pg.currentCell++;
-
-               // Get the page number this cell describes
-               int pagenum = get4(&pg.data[celloff]);
-
-               // And the highest integer key, which starts at offset 4 within the cell.
-               int64_t intkey = 0;
-               get_varint(&pg.data[celloff + 4], &intkey);
-
-               //wxLogDebug("%*.*sinternal - right %lld celloff %d pagenum %d intkey %lld", (stack.size() - 1) * 2, (stack.size() - 1) * 2, " ", right, celloff, pagenum, intkey);
-
-               // Stack the described page if we're not looking for a specific blockid
-               // or if this page contains the given blockid.
-               if (!blockid || blockid <= intkey)
-               {
-                  stack.push_back({pagenum, 0, 0});
-                  stacked = true;
-                  break;
-               }
-            }
-
-            // If we pushed a new page onto the stack, we need to jump back up
-            // to read the page
-            if (stacked)
-            {
-               continue;
-            }
-         }
+   if (blockid != 0)
+   {
+      int rc = sqlite3_bind_int64(stmt, 1, blockid);
 
-         // We've exhausted all the cells with this page, so we stack the right-most
-         // leaf page.  Ensure we only process it once.
-         if (right)
-         {
-            stack.push_back({right, 0, 0});
-            right = 0;
-            continue;
-         }
-      }
-      // Process a leaf table b-tree page
-      else if (pg.data[0] == 0x0d)
+      if (rc != SQLITE_OK)
       {
-         // Iterate over the cells
-         //
-         // If we're not looking for a specific blockid, then just accumulate the
-         // payload sizes. We will be reading every leaf page in the sampleblocks
-         // table.
-         //
-         // Otherwise we break out when we find the matching blockid. In this case,
-         // we only ever look at 1 leaf page.
-         bool stop = false;
-         for (int i = 0; i < pg.numCells; i++)
-         {
-            // Get the offset to this cell using the offset in the cell pointer
-            // array.
-            //
-            // The cell pointer array starts immediately after the page header
-            // at offset 8 and the retrieved offset is from the beginning of
-            // the page.
-            int celloff = get2(&pg.data[8 + (i * 2)]);
-
-            // Get the total payload size in bytes of the described row.
-            int64_t payload = 0;
-            int digits = get_varint(&pg.data[celloff], &payload);
-
-            // Get the integer key for this row.
-            int64_t intkey = 0;
-            get_varint(&pg.data[celloff + digits], &intkey);
-
-            //wxLogDebug("%*.*sleaf - celloff %4d intkey %lld payload %lld", (stack.size() - 1) * 2, (stack.size() - 1) * 2, " ", celloff, intkey, payload);
-
-            // Add this payload size to the total if we're not looking for a specific
-            // blockid
-            if (!blockid)
-            {
-               total += payload;
-            }
-            // Otherwise, return the payload size for a matching row
-            else if (blockid == intkey)
-            {
-               return payload;
-            }
-         }
+         conn.ThrowException(false);
       }
+   }
 
-      // Done with the current branch, so pop back up to the previous one (if any)
-      stack.pop_back();
-   } while (!stack.empty());
-
-   // Return the total used for all sample blocks
-   return total;
-}
-
-// Retrieves a 2-byte big-endian integer from the page data
-unsigned int ProjectFileIO::get2(const unsigned char *ptr)
-{
-   return (ptr[0] << 8) | ptr[1];
-}
-
-// Retrieves a 4-byte big-endian integer from the page data
-unsigned int ProjectFileIO::get4(const unsigned char *ptr)
-{
-   return ((unsigned int) ptr[0] << 24) |
-          ((unsigned int) ptr[1] << 16) |
-          ((unsigned int) ptr[2] << 8)  |
-          ((unsigned int) ptr[3]);
-}
-
-// Retrieves a variable length integer from the page data. Returns the
-// number of digits used to encode the integer and the stores the
-// value at the given location.
-int ProjectFileIO::get_varint(const unsigned char *ptr, int64_t *out)
-{
-   int64_t val = 0;
-   int i;
+   int rc = sqlite3_step(stmt);
 
-   for (i = 0; i < 8; ++i)
+   if (rc != SQLITE_ROW)
    {
-      val = (val << 7) + (ptr[i] & 0x7f);
-      if ((ptr[i] & 0x80) == 0)
-      {
-         *out = val;
-         return i + 1;
-      }
+      conn.ThrowException(false);
    }
 
-   val = (val << 8) + (ptr[i] & 0xff);
-   *out = val;
+   const int64_t size = sqlite3_column_int64(stmt, 0);
 
-   return 9;
+   return size;
 }
 
 InvisibleTemporaryProject::InvisibleTemporaryProject()
-- 
2.33.1